diff --git a/lib/chai/utils/addProperty.js b/lib/chai/utils/addProperty.js
index 1358ad9..6e535db 100644
--- a/lib/chai/utils/addProperty.js
+++ b/lib/chai/utils/addProperty.js
@@ -6,6 +6,7 @@
 
 var chai = require('../../chai');
 var flag = require('./flag');
+var isProxyEnabled = require('./isProxyEnabled');
 var transferFlags = require('./transferFlags');
 
 /**
@@ -39,10 +40,12 @@ module.exports = function addProperty(ctx, name, getter) {
 
   Object.defineProperty(ctx, name,
     { get: function propertyGetter() {
-        var keep_ssfi = flag(this, 'keep_ssfi');
-        var old_ssfi = flag(this, 'ssfi');
-        if (!keep_ssfi && old_ssfi)
-          flag(this, 'ssfi', propertyGetter);
+        if (!isProxyEnabled()) {
+          var keep_ssfi = flag(this, 'keep_ssfi');
+          var old_ssfi = flag(this, 'ssfi');
+          if (!keep_ssfi && old_ssfi)
+            flag(this, 'ssfi', propertyGetter);
+        }
 
         var result = getter.call(this);
         if (result !== undefined)
diff --git a/lib/chai/utils/overwriteProperty.js b/lib/chai/utils/overwriteProperty.js
index 1f8a28b..0ffb268 100644
--- a/lib/chai/utils/overwriteProperty.js
+++ b/lib/chai/utils/overwriteProperty.js
@@ -6,6 +6,7 @@
 
 var chai = require('../../chai');
 var flag = require('./flag');
+var isProxyEnabled = require('./isProxyEnabled');
 var transferFlags = require('./transferFlags');
 
 /**
@@ -51,10 +52,12 @@ module.exports = function overwriteProperty(ctx, name, getter) {
 
   Object.defineProperty(ctx, name,
     { get: function overwritingPropertyGetter() {
-        var keep_ssfi = flag(this, 'keep_ssfi');
-        var old_ssfi = flag(this, 'ssfi');
-        if (!keep_ssfi && old_ssfi)
-          flag(this, 'ssfi', overwritingPropertyGetter);
+        if (!isProxyEnabled()) {
+          var keep_ssfi = flag(this, 'keep_ssfi');
+          var old_ssfi = flag(this, 'ssfi');
+          if (!keep_ssfi && old_ssfi)
+            flag(this, 'ssfi', overwritingPropertyGetter);
+        }
 
         flag(this, 'keep_ssfi', true);
         var result = getter(_super).call(this);
diff --git a/lib/chai/utils/proxify.js b/lib/chai/utils/proxify.js
index ed73e66..a9ba811 100644
--- a/lib/chai/utils/proxify.js
+++ b/lib/chai/utils/proxify.js
@@ -1,4 +1,5 @@
 var config = require('../config');
+var flag = require('./flag');
 var getProperties = require('./getProperties');
 var isProxyEnabled = require('./isProxyEnabled');
 
@@ -27,6 +28,8 @@ var isProxyEnabled = require('./isProxyEnabled');
  * @name proxify
  */
 
+var builtins = ['__flags', '__methods', '_obj', 'assert'];
+
 module.exports = function proxify(obj, nonChainableMethodName) {
   if (!isProxyEnabled()) return obj;
 
@@ -48,7 +51,7 @@ module.exports = function proxify(obj, nonChainableMethodName) {
 
         var orderedProperties = getProperties(target).filter(function(property) {
           return !Object.prototype.hasOwnProperty(property) &&
-            ['__flags', '__methods', '_obj', 'assert'].indexOf(property) === -1;
+            builtins.indexOf(property) === -1;
         }).sort(function(a, b) {
           return stringDistance(property, a) - stringDistance(property, b);
         });
@@ -64,6 +67,10 @@ module.exports = function proxify(obj, nonChainableMethodName) {
         }
       }
 
+      if (builtins.indexOf(property) === -1) {
+        flag(target, 'ssfi', proxyGetter);
+      }
+
       return Reflect.get(target, property);
     }
   });
diff --git a/test/configuration.js b/test/configuration.js
index f83d366..77d2053 100644
--- a/test/configuration.js
+++ b/test/configuration.js
@@ -99,6 +99,10 @@ describe('configuration', function () {
 
         it('should include Chai frames in stack trace', function () {
           expect(caughtErr.stack).to.contain('propertyGetter');
+
+          if (typeof Proxy !== 'undefined' && typeof Reflect !== 'undefined') {
+            expect(caughtErr.stack).to.contain('proxyGetter');
+          }
         });
 
         it('should include user frames in stack trace', function () {
@@ -121,6 +125,10 @@ describe('configuration', function () {
 
         it('should include Chai frames in stack trace', function () {
           expect(caughtErr.stack).to.contain('overwritingPropertyGetter');
+
+          if (typeof Proxy !== 'undefined' && typeof Reflect !== 'undefined') {
+            expect(caughtErr.stack).to.contain('proxyGetter');
+          }
         });
 
         it('should include user frames in stack trace', function () {
@@ -233,6 +241,10 @@ describe('configuration', function () {
 
         it('should not include Chai frames in stack trace', function () {
           expect(caughtErr.stack).to.not.contain('propertyGetter');
+
+          if (typeof Proxy !== 'undefined' && typeof Reflect !== 'undefined') {
+            expect(caughtErr.stack).to.not.contain('proxyGetter');
+          }
         });
 
         it('should include user frames in stack trace', function () {
@@ -255,6 +267,10 @@ describe('configuration', function () {
 
         it('should not include Chai frames in stack trace', function () {
           expect(caughtErr.stack).to.not.contain('overwritingPropertyGetter');
+
+          if (typeof Proxy !== 'undefined' && typeof Reflect !== 'undefined') {
+            expect(caughtErr.stack).to.not.contain('proxyGetter');
+          }
         });
 
         it('should include user frames in stack trace', function () {