--- a/layout/painting/nsDisplayList.cpp
+++ b/layout/painting/nsDisplayList.cpp
@@ -6276,16 +6276,17 @@ nsDisplayOpacity::CreateWebRenderCommand
 
     OpAddCompositorAnimations
       anim(CompositorAnimations(animationInfo.GetAnimations(), animationsId),
            void_t(), opacityForCompositor);
     aManager->WrBridge()->AddWebRenderParentCommand(anim);
     aManager->AddActiveCompositorAnimationId(animationsId);
   } else if (animationsId) {
     aManager->AddCompositorAnimationsIdForDiscard(animationsId);
+    animationsId = 0;
   }
 
   nsTArray<mozilla::wr::WrFilterOp> filters;
   StackingContextHelper sc(aSc,
                            aBuilder,
                            aDisplayListBuilder,
                            this,
                            &mList,
@@ -8050,16 +8051,17 @@ nsDisplayTransform::CreateWebRenderComma
 
     OpAddCompositorAnimations
       anim(CompositorAnimations(animationInfo.GetAnimations(), animationsId),
            transformForCompositor, void_t());
     aManager->WrBridge()->AddWebRenderParentCommand(anim);
     aManager->AddActiveCompositorAnimationId(animationsId);
   } else if (animationsId) {
     aManager->AddCompositorAnimationsIdForDiscard(animationsId);
+    animationsId = 0;
   }
 
   gfx::Matrix4x4Typed<LayerPixel, LayerPixel> boundTransform = ViewAs<gfx::Matrix4x4Typed<LayerPixel, LayerPixel>>(newTransformMatrix);
 
   nsTArray<mozilla::wr::WrFilterOp> filters;
   StackingContextHelper sc(aSc,
                            aBuilder,
                            aDisplayListBuilder,