--- a/layout/style/nsAnimationManager.cpp
+++ b/layout/style/nsAnimationManager.cpp
@@ -786,17 +786,17 @@ CSSAnimationBuilder::BuildAnimationFrame
       }
     }
 
     // If we have a keyframe at the same offset with the same timing
     // function we should merge our (unique) values into it.
     // Otherwise, we should update the existing keyframe with only the
     // unique properties.
     //
-    // Bug 1216843: We should also match composite modes here.
+    // Bug 1293490: We should also match composite modes here.
     Keyframe* existingKeyframe = nullptr;
     // Don't bother searching for an existing keyframe if we don't
     // have anything to contribute to it.
     if (!uniquePropertyValues.IsEmpty()) {
       for (size_t i = keyframeIdx; i < keyframes.Length(); i++) {
         Keyframe& kf = keyframes[i];
         if (kf.mOffset.value() != currentOffset) {
           break;

--- a/testing/web-platform/meta/web-animations/interfaces/Animatable/animate.html.ini
+++ b/testing/web-platform/meta/web-animations/interfaces/Animatable/animate.html.ini
@@ -11,28 +11,28 @@
   [Element.animate() accepts a one property two value property-indexed keyframes specification where the first value is invalid]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [Element.animate() accepts a one property two value property-indexed keyframes specification where the second value is invalid]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
-  [Element.animate() accepts a keyframe sequence with different composite values, but the same composite value for a given offset]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
-
   [Element.animate() accepts a one property one keyframe sequence]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [Element.animate() accepts a single keyframe sequence with omitted offsets]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
+  [Element.animate() accepts a keyframe sequence with different composite values, but the same composite value for a given offset]
+    expected: FAIL
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1291468
+
   [Element.animate() accepts a two property keyframe sequence where one property is missing from the first keyframe]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [Element.animate() accepts a two property keyframe sequence where one property is missing from the last keyframe]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 

--- a/testing/web-platform/meta/web-animations/interfaces/KeyframeEffect/constructor.html.ini
+++ b/testing/web-platform/meta/web-animations/interfaces/KeyframeEffect/constructor.html.ini
@@ -1,25 +1,21 @@
 [constructor.html]
   type: testharness
   [composite values are parsed correctly when passed to the KeyframeEffectReadOnly constructor in property-indexed keyframes]
     expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1291468
 
   [composite values are parsed correctly when passed to the KeyframeEffectReadOnly constructor in regular keyframes]
     expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1291468
 
   [composite values are parsed correctly when passed to the KeyframeEffectReadOnly constructor in KeyframeTimingOptions]
     expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
-
-  [a KeyframeEffectReadOnly can be constructed with a keyframe sequence with different composite values, but the same composite value for a given offset]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [a KeyframeEffectReadOnly can be constructed with a one property one value property-indexed keyframes specification]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [a KeyframeEffectReadOnly constructed with a one property one value property-indexed keyframes specification roundtrips]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
@@ -59,16 +55,20 @@
   [a KeyframeEffectReadOnly can be constructed with a single keyframe sequence with omitted offsets]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [a KeyframeEffectReadOnly constructed with a single keyframe sequence with omitted offsets roundtrips]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
+  [a KeyframeEffectReadOnly can be constructed with a keyframe sequence with different composite values, but the same composite value for a given offset]
+    expected: FAIL
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1291468
+
   [a KeyframeEffectReadOnly can be constructed with a two property keyframe sequence where one property is missing from the first keyframe]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [a KeyframeEffectReadOnly constructed with a two property keyframe sequence where one property is missing from the first keyframe roundtrips]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 

--- a/testing/web-platform/meta/web-animations/interfaces/KeyframeEffect/setKeyframes.html.ini
+++ b/testing/web-platform/meta/web-animations/interfaces/KeyframeEffect/setKeyframes.html.ini
@@ -11,29 +11,29 @@
   [Keyframes can be replaced with a one property two value property-indexed keyframes specification where the first value is invalid]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [Keyframes can be replaced with a one property two value property-indexed keyframes specification where the second value is invalid]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
+  [Keyframes can be replaced with a one property one keyframe sequence]
+    expected: FAIL
+
+  [Keyframes can be replaced with a single keyframe sequence with omitted offsets]
+    expected: FAIL
+
   [Keyframes can be replaced with a keyframe sequence with different composite values, but the same composite value for a given offset]
     expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216843
+    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1291468
 
   [Keyframes can be replaced with a two property keyframe sequence where one property is missing from the first keyframe]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
   [Keyframes can be replaced with a two property keyframe sequence where one property is missing from the last keyframe]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1216844
 
-  [Keyframes can be replaced with a one property one keyframe sequence]
-    expected: FAIL
-
-  [Keyframes can be replaced with a single keyframe sequence with omitted offsets]
-    expected: FAIL
-
   [Keyframes can be replaced with a single keyframe sequence with string offset]
     expected: FAIL