diff --git a/bevy_legion/legion_core/src/filter.rs b/bevy_legion/legion_core/src/filter.rs
index 96782c4fa9..f4ea211e1b 100644
--- a/bevy_legion/legion_core/src/filter.rs
+++ b/bevy_legion/legion_core/src/filter.rs
@@ -95,6 +95,9 @@ impl FilterResult for Option<bool> {
 pub trait Filter<T: Copy>: Send + Sync + Sized {
     type Iter: Iterator + Send + Sync;
 
+    // Called when a query is about to begin execution.
+    fn init(&self) {}
+
     /// Pulls iterator data out of the source.
     fn collect(&self, source: T) -> Self::Iter;
 
@@ -168,6 +171,9 @@ pub trait EntityFilter: Send + Clone {
     type ChunksetFilter: for<'a> Filter<ChunksetFilterData<'a>> + Clone;
     type ChunkFilter: for<'a> Filter<ChunkFilterData<'a>> + Clone;
 
+    /// Initializes the entity filter for iteration.
+    fn init(&self);
+
     /// Gets mutable references to both inner filters.
     fn filters(
         &self,
@@ -239,6 +245,12 @@ where
     type ChunksetFilter = S;
     type ChunkFilter = C;
 
+    fn init(&self) {
+        self.arch_filter.init();
+        self.chunkset_filter.init();
+        self.chunk_filter.init();
+    }
+
     fn filters(
         &self,
     ) -> (
@@ -380,7 +392,7 @@ impl<'a, 'b, F: Filter<ArchetypeFilterData<'a>>> Iterator for FilterArchIter<'a,
     }
 }
 
-/// An iterator which yields the index of chunks that match a filter.
+/// An iterator which yields the index of chuinks that match a filter.
 pub struct FilterChunkIter<'a, 'b, F: Filter<ChunksetFilterData<'a>>> {
     filter: &'b F,
     chunks: Enumerate<F::Iter>,
@@ -458,6 +470,9 @@ pub struct Passthrough;
 impl<'a> Filter<ArchetypeFilterData<'a>> for Passthrough {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, arch: ArchetypeFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(arch.component_types.len())
@@ -470,6 +485,9 @@ impl<'a> Filter<ArchetypeFilterData<'a>> for Passthrough {
 impl<'a> Filter<ChunksetFilterData<'a>> for Passthrough {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, sets: ChunksetFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(sets.archetype_data.len())
@@ -482,6 +500,9 @@ impl<'a> Filter<ChunksetFilterData<'a>> for Passthrough {
 impl<'a> Filter<ChunkFilterData<'a>> for Passthrough {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, chunk: ChunkFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(chunk.chunks.len())
@@ -520,6 +541,9 @@ impl ActiveFilter for Any {}
 impl<'a> Filter<ArchetypeFilterData<'a>> for Any {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, arch: ArchetypeFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(arch.component_types.len())
@@ -532,6 +556,9 @@ impl<'a> Filter<ArchetypeFilterData<'a>> for Any {
 impl<'a> Filter<ChunksetFilterData<'a>> for Any {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, sets: ChunksetFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(sets.archetype_data.len())
@@ -544,6 +571,9 @@ impl<'a> Filter<ChunksetFilterData<'a>> for Any {
 impl<'a> Filter<ChunkFilterData<'a>> for Any {
     type Iter = Take<Repeat<()>>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, chunk: ChunkFilterData<'a>) -> Self::Iter {
         std::iter::repeat(()).take(chunk.chunks.len())
@@ -592,6 +622,9 @@ impl<F> ActiveFilter for Not<F> {}
 impl<'a, T: Copy, F: Filter<T>> Filter<T> for Not<F> {
     type Iter = F::Iter;
 
+    #[inline]
+    fn init(&self) { self.filter.init(); }
+
     #[inline]
     fn collect(&self, source: T) -> Self::Iter { self.filter.collect(source) }
 
@@ -648,6 +681,9 @@ impl<T> ActiveFilter for And<(T,)> {}
 impl<'a, T: Copy, F: Filter<T>> Filter<T> for And<(F,)> {
     type Iter = F::Iter;
 
+    #[inline]
+    fn init(&self) { self.filters.0.init(); }
+
     #[inline]
     fn collect(&self, source: T) -> Self::Iter { self.filters.0.collect(source) }
 
@@ -717,6 +753,13 @@ macro_rules! impl_and_filter {
             // type Iter = crate::zip::Zip<( $( $ty::Iter ),* )>;
             type Iter = recursive_zip!(@type $($ty::Iter),*);
 
+            #[inline]
+            fn init(&self) {
+                #![allow(non_snake_case)]
+                let ($( $ty, )*) = &self.filters;
+                $( $ty.init(); )*
+            }
+
             fn collect(&self, source: T) -> Self::Iter {
                 #![allow(non_snake_case)]
                 let ($( $ty, )*) = &self.filters;
@@ -818,6 +861,13 @@ macro_rules! impl_or_filter {
             // type Iter = crate::zip::Zip<( $( $ty::Iter ),* )>;
             type Iter = recursive_zip!(@type $($ty::Iter),*);
 
+            #[inline]
+            fn init(&self) {
+                #![allow(non_snake_case)]
+                let ($( $ty, )*) = &self.filters;
+                $( $ty.init(); )*
+            }
+
             fn collect(&self, source: T) -> Self::Iter {
                 #![allow(non_snake_case)]
                 let ($( $ty, )*) = &self.filters;
@@ -905,7 +955,7 @@ impl_or_filter!(A => a, B => b, C => c, D => d, E => e, F => f, G => g, H => h,
 impl_or_filter!(A => a, B => b, C => c, D => d, E => e, F => f, G => g, H => h, I => i, J => j, K => k);
 impl_or_filter!(A => a, B => b, C => c, D => d, E => e, F => f, G => g, H => h, I => i, J => j, K => k, L => l);
 
-/// A filter which requires that all chunks contain entity data components of type `T`.
+/// A filter qhich requires that all chunks contain entity data components of type `T`.
 #[derive(Debug)]
 pub struct ComponentFilter<T>(PhantomData<T>);
 
@@ -923,6 +973,9 @@ impl<T> Clone for ComponentFilter<T> {
 impl<'a, T: Component> Filter<ArchetypeFilterData<'a>> for ComponentFilter<T> {
     type Iter = SliceVecIter<'a, ComponentTypeId>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, source: ArchetypeFilterData<'a>) -> Self::Iter {
         source.component_types.iter()
@@ -995,6 +1048,9 @@ impl<T> Clone for TagFilter<T> {
 impl<'a, T: Tag> Filter<ArchetypeFilterData<'a>> for TagFilter<T> {
     type Iter = SliceVecIter<'a, TagTypeId>;
 
+    #[inline]
+    fn init(&self) {}
+
     #[inline]
     fn collect(&self, source: ArchetypeFilterData<'a>) -> Self::Iter { source.tag_types.iter() }
 
@@ -1067,6 +1123,9 @@ impl<'a, T> Clone for TagValueFilter<'a, T> {
 impl<'a, 'b, T: Tag> Filter<ChunksetFilterData<'a>> for TagValueFilter<'b, T> {
     type Iter = Iter<'a, T>;
 
+    #[inline]
+    fn init(&self) {}
+
     fn collect(&self, source: ChunksetFilterData<'a>) -> Self::Iter {
         unsafe {
             source
@@ -1132,14 +1191,16 @@ impl<'a, T> std::ops::BitOr<Passthrough> for TagValueFilter<'a, T> {
 /// chunk since the last time the filter was executed.
 #[derive(Debug)]
 pub struct ComponentChangedFilter<T: Component> {
-    last_read_version: AtomicU64,
+    high_water_mark: AtomicU64,
+    version_threshold: AtomicU64,
     phantom: PhantomData<T>,
 }
 
 impl<T: Component> ComponentChangedFilter<T> {
     fn new() -> ComponentChangedFilter<T> {
         ComponentChangedFilter {
-            last_read_version: AtomicU64::new(0),
+            high_water_mark: AtomicU64::new(0),
+            version_threshold: AtomicU64::new(0),
             phantom: PhantomData,
         }
     }
@@ -1150,29 +1211,63 @@ impl<T: Component> ActiveFilter for ComponentChangedFilter<T> {}
 impl<T: Component> Clone for ComponentChangedFilter<T> {
     fn clone(&self) -> Self {
         Self {
-            last_read_version: AtomicU64::new(self.last_read_version.load(Ordering::Relaxed)),
+            high_water_mark: AtomicU64::new(self.high_water_mark.load(Ordering::Relaxed)),
+            version_threshold: AtomicU64::new(self.version_threshold.load(Ordering::Relaxed)),
             phantom: PhantomData,
         }
     }
 }
 
 impl<'a, T: Component> Filter<ChunkFilterData<'a>> for ComponentChangedFilter<T> {
-    type Iter = Iter<'a, ComponentStorage>;
+    type Iter = ComponentChangedState<'a, ComponentStorage>;
 
-    fn collect(&self, source: ChunkFilterData<'a>) -> Self::Iter { source.chunks.iter() }
+    #[inline]
+    fn init(&self) {
+        let version = self.high_water_mark.load(Ordering::Relaxed);
+        let mut threshold = self.version_threshold.load(Ordering::Relaxed);
+        if threshold < version {
+            loop {
+                match self.version_threshold.compare_exchange_weak(
+                    threshold,
+                    version,
+                    Ordering::Relaxed,
+                    Ordering::Relaxed,
+                ) {
+                    Ok(_) => break,
+                    Err(stored_last_read) => {
+                        threshold = stored_last_read;
+                        if threshold >= version {
+                            // matched version is already considered visited, update no longer needed
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fn collect(&self, source: ChunkFilterData<'a>) -> Self::Iter {
+        let compare_version = self.version_threshold.load(Ordering::Relaxed);
+        ComponentChangedState {
+            iter: source.chunks.iter(),
+            version_threshold: compare_version,
+        }
+    }
 
     #[inline]
     fn is_match(&self, item: &<Self::Iter as Iterator>::Item) -> Option<bool> {
-        let components = item.components(ComponentTypeId::of::<T>());
+        let (version_threshold, storage) = item;
+
+        let components = storage.components(ComponentTypeId::of::<T>());
         if components.is_none() {
             return Some(false);
         }
 
         let version = components.unwrap().version();
-        let mut last_read = self.last_read_version.load(Ordering::Relaxed);
+        let mut last_read = self.high_water_mark.load(Ordering::Relaxed);
         if last_read < version {
             loop {
-                match self.last_read_version.compare_exchange_weak(
+                match self.high_water_mark.compare_exchange_weak(
                     last_read,
                     version,
                     Ordering::Relaxed,
@@ -1181,13 +1276,16 @@ impl<'a, T: Component> Filter<ChunkFilterData<'a>> for ComponentChangedFilter<T>
                     Ok(_) => break,
                     Err(stored_last_read) => {
                         last_read = stored_last_read;
-                        if last_read < version {
+                        if last_read >= version {
                             // matched version is already considered visited, update no longer needed
                             break;
                         }
                     }
                 }
             }
+        }
+
+        if version > *version_threshold {
             Some(true)
         } else {
             Some(false)
@@ -1195,6 +1293,19 @@ impl<'a, T: Component> Filter<ChunkFilterData<'a>> for ComponentChangedFilter<T>
     }
 }
 
+pub struct ComponentChangedState<'a, T: Component> {
+    iter: Iter<'a, T>,
+    version_threshold: u64,
+}
+
+impl<'a, T: Component> Iterator for ComponentChangedState<'a, T> {
+    type Item = (u64, &'a T);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|c| (self.version_threshold, c))
+    }
+}
+
 impl<'a, T: Component> std::ops::Not for ComponentChangedFilter<T> {
     type Output = Not<Self>;
 
@@ -1241,6 +1352,7 @@ impl<'a, T: Component> std::ops::BitOr<Passthrough> for ComponentChangedFilter<T
 #[cfg(test)]
 mod test {
     use super::filter_fns::*;
+    use crate::prelude::*;
 
     #[test]
     pub fn create() {
@@ -1249,4 +1361,40 @@ mod test {
         let filter = component::<usize>() | tag_value(&5isize);
         tracing::trace!(?filter);
     }
+
+    #[test]
+    fn component_changed_filter() {
+        let _ = tracing_subscriber::fmt::try_init();
+
+        let universe = Universe::new();
+        let mut world = universe.create_world();
+
+        let entity1 = world.insert((), vec![(1usize,)])[0];
+        let entity2 = world.insert((), vec![(2usize, false)])[0];
+
+        let query = <Read<usize>>::query().filter(changed::<usize>());
+
+        assert_eq!(2, query.iter_chunks(&world).collect::<Vec<_>>().len());
+
+        *world.get_component_mut::<usize>(entity1).unwrap() = 3usize;
+
+        assert_eq!(1, query.iter_chunks(&world).collect::<Vec<_>>().len());
+
+        *world.get_component_mut::<usize>(entity1).unwrap() = 4usize;
+        *world.get_component_mut::<usize>(entity2).unwrap() = 5usize;
+
+        assert_eq!(2, query.iter_chunks(&world).collect::<Vec<_>>().len());
+
+        *world.get_component_mut::<usize>(entity1).unwrap() = 6usize;
+        *world.get_component_mut::<usize>(entity1).unwrap() = 7usize;
+        *world.get_component_mut::<usize>(entity2).unwrap() = 8usize;
+
+        assert_eq!(2, query.iter_chunks(&world).collect::<Vec<_>>().len());
+
+        *world.get_component_mut::<usize>(entity2).unwrap() = 6usize;
+        *world.get_component_mut::<usize>(entity2).unwrap() = 7usize;
+        *world.get_component_mut::<usize>(entity1).unwrap() = 8usize;
+
+        assert_eq!(2, query.iter_chunks(&world).collect::<Vec<_>>().len());
+    }
 }
diff --git a/bevy_legion/legion_core/src/query.rs b/bevy_legion/legion_core/src/query.rs
index 292f4a11c5..04a4cbdacf 100644
--- a/bevy_legion/legion_core/src/query.rs
+++ b/bevy_legion/legion_core/src/query.rs
@@ -949,6 +949,7 @@ where
         &'a self,
         world: &'data World,
     ) -> ChunkViewIter<'data, 'a, V, F::ArchetypeFilter, F::ChunksetFilter, F::ChunkFilter> {
+        self.filter.init();
         let (arch_filter, chunkset_filter, chunk_filter) = self.filter.filters();
         let storage = world.storage();
         let archetypes = arch_filter
@@ -1190,6 +1191,7 @@ where
         <F::ChunksetFilter as Filter<ChunksetFilterData<'data>>>::Iter: FissileIterator,
         <F::ChunkFilter as Filter<ChunkFilterData<'data>>>::Iter: FissileIterator,
     {
+        self.filter.init();
         let (arch_filter, chunkset_filter, chunk_filter) = self.filter.filters();
         let storage = world.storage();
         let archetypes = FissileEnumerate::new(arch_filter.collect(ArchetypeFilterData {
diff --git a/bevy_legion/legion_core/src/storage.rs b/bevy_legion/legion_core/src/storage.rs
index d54302dfaf..276d6f2a49 100644
--- a/bevy_legion/legion_core/src/storage.rs
+++ b/bevy_legion/legion_core/src/storage.rs
@@ -1425,7 +1425,10 @@ impl ComponentStorage {
         // free component memory
         unsafe {
             let ptr = self.component_data.take().unwrap();
-            std::alloc::dealloc(ptr.as_ptr(), self.component_layout);
+
+            if self.component_layout.size() > 0 {
+                std::alloc::dealloc(ptr.as_ptr(), self.component_layout);
+            }
         }
 
         self.update_mem_gauge();
@@ -1446,13 +1449,18 @@ impl ComponentStorage {
 
         unsafe {
             // allocating backing store
-            let ptr = std::alloc::alloc(self.component_layout);
-            self.component_data = Some(NonNull::new_unchecked(ptr));
+            if self.component_layout.size() > 0 {
+                let ptr = std::alloc::alloc(self.component_layout);
+                self.component_data = Some(NonNull::new_unchecked(ptr));
 
-            // update accessor pointers
-            for (type_id, component) in (&mut *self.component_info.get()).iter_mut() {
-                let &offset = self.component_offsets.get(type_id).unwrap();
-                *component.ptr.get_mut() = ptr.add(offset);
+                // update accessor pointers
+                for (type_id, component) in (&mut *self.component_info.get()).iter_mut() {
+                    let &offset = self.component_offsets.get(type_id).unwrap();
+                    *component.ptr.get_mut() = ptr.add(offset);
+                }
+            } else {
+                self.component_data =
+                    Some(NonNull::new(self.component_layout.align() as *mut u8).unwrap());
             }
         }
 
@@ -1516,8 +1524,10 @@ impl Drop for ComponentStorage {
             self.update_count_gauge();
 
             // free the chunk's memory
-            unsafe {
-                std::alloc::dealloc(ptr.as_ptr(), self.component_layout);
+            if self.component_layout.size() > 0 {
+                unsafe {
+                    std::alloc::dealloc(ptr.as_ptr(), self.component_layout);
+                }
             }
         }
     }
diff --git a/bevy_legion/legion_core/src/world.rs b/bevy_legion/legion_core/src/world.rs
index 23acc68de9..ac56bb6d5b 100644
--- a/bevy_legion/legion_core/src/world.rs
+++ b/bevy_legion/legion_core/src/world.rs
@@ -462,8 +462,6 @@ impl World {
     /// This function has the overhead of moving the entity to either an existing or new archetype,
     /// causing a memory copy of the entity to a new location. This function should not be used
     /// multiple times in successive order.
-    ///
-    /// `World::add_components` should be used for adding multiple omponents to an entity at once.
     pub fn add_component<T: Component>(
         &mut self,
         entity: Entity,
diff --git a/bevy_legion/legion_systems/src/schedule.rs b/bevy_legion/legion_systems/src/schedule.rs
index 45bb7cf3dc..823261d7ac 100644
--- a/bevy_legion/legion_systems/src/schedule.rs
+++ b/bevy_legion/legion_systems/src/schedule.rs
@@ -168,8 +168,13 @@ impl Executor {
                     64,
                     Default::default(),
                 );
-            let mut component_mutated =
-                FxHashMap::<ComponentTypeId, Vec<usize>>::with_capacity_and_hasher(
+            let mut component_last_mutated =
+                FxHashMap::<ComponentTypeId, usize>::with_capacity_and_hasher(
+                    64,
+                    Default::default(),
+                );
+            let mut component_last_read =
+                FxHashMap::<ComponentTypeId, usize>::with_capacity_and_hasher(
                     64,
                     Default::default(),
                 );
@@ -220,23 +225,28 @@ impl Executor {
 
                 // find component access dependencies
                 let mut comp_dependencies = FxHashSet::default();
-                for comp in read_comp {
-                    if let Some(ns) = component_mutated.get(comp) {
-                        for n in ns {
-                            comp_dependencies.insert(*n);
-                        }
-                    }
-                }
                 for comp in write_comp {
-                    if let Some(ns) = component_mutated.get(comp) {
-                        for n in ns {
-                            comp_dependencies.insert(*n);
-                        }
+                    // Writes have to be exclusive, so we are dependent on reads too
+                    trace!(component = ?comp, "Write component");
+                    if let Some(n) = component_last_read.get(comp) {
+                        trace!(system_index = n, "Added read dependency");
+                        comp_dependencies.insert(*n);
                     }
-                    component_mutated
-                        .entry(*comp)
-                        .or_insert_with(Vec::new)
-                        .push(i);
+                    if let Some(n) = component_last_mutated.get(comp) {
+                        trace!(system_index = n, "Added write dependency");
+                        comp_dependencies.insert(*n);
+                    }
+                    component_last_mutated.insert(*comp, i);
+                }
+
+                // Do reads after writes to ensure we don't overwrite last_read
+                for comp in read_comp {
+                    trace!(component = ?comp, "Read component");
+                    if let Some(n) = component_last_mutated.get(comp) {
+                        trace!(system_index = n, "Added write dependency");
+                        comp_dependencies.insert(*n);
+                    }
+                    component_last_read.insert(*comp, i);
                 }
 
                 trace!(depentants = ?comp_dependencies, "Computed dynamic dependants");
diff --git a/bevy_legion/legion_systems/src/system.rs b/bevy_legion/legion_systems/src/system.rs
index 80e721ab44..ee14f14984 100644
--- a/bevy_legion/legion_systems/src/system.rs
+++ b/bevy_legion/legion_systems/src/system.rs
@@ -1627,11 +1627,11 @@ mod tests {
         struct Comp2(f32, f32, f32);
 
         let components = vec![
-            (Pos(69., 69., 69.), Vel(69., 69., 69.)),
-            (Pos(69., 69., 69.), Vel(69., 69., 69.)),
+            (Comp1(69., 69., 69.), Comp2(69., 69., 69.)),
+            (Comp1(69., 69., 69.), Comp2(69., 69., 69.)),
         ];
 
-        let mut expected = HashMap::<Entity, (Pos, Vel)>::new();
+        let mut expected = HashMap::<Entity, (Comp1, Comp2)>::new();
 
         for (i, e) in world.insert((), components.clone()).iter().enumerate() {
             if let Some((pos, rot)) = components.get(i) {
@@ -1670,7 +1670,7 @@ mod tests {
         let system3 = SystemBuilder::<()>::new("TestSystem3")
             .with_query(<(Write<Comp1>, Write<Comp2>)>::query())
             .build(move |_, world, _, query| {
-                query.iter_mut(world).for_each(|(mut one, two)| {
+                query.iter_mut(world).for_each(|(mut one, mut two)| {
                     assert_eq!(one.0, 456.);
                     assert_eq!(one.1, 456.);
                     assert_eq!(one.2, 456.);
@@ -1683,9 +1683,9 @@ mod tests {
                     one.1 = 789.;
                     one.2 = 789.;
 
-                    one.0 = 789.;
-                    one.1 = 789.;
-                    one.2 = 789.;
+                    two.0 = 789.;
+                    two.1 = 789.;
+                    two.2 = 789.;
                 });
             });