diff --git a/layout/reftests/layers/reftest.list b/layout/reftests/layers/reftest.list
index f7d5e6a26ebf..39863da47357 100644
--- a/layout/reftests/layers/reftest.list
+++ b/layout/reftests/layers/reftest.list
@@ -24,7 +24,7 @@ skip-if(!asyncPan) != pull-background-displayport-5.html about:blank
 skip-if(!asyncPan) != pull-background-displayport-6.html about:blank # fails with non-overlay scrollbars and event regions due to bug 1148515
 
 fuzzy(0-2,0-30150) == opacity-blending.html opacity-blending-ref.html
-fuzzy(0-16,0-5) == mask-layer-transform.html mask-layer-transform-ref.html
+fuzzy(0-16,0-20) == mask-layer-transform.html mask-layer-transform-ref.html
 fuzzy-if(gtkWidget,0-1,0-17) fuzzy-if(Android,0-3,0-4) == forced-bg-color-outside-visible-region.html forced-bg-color-outside-visible-region-ref.html
 != layerize-over-fixed-bg-1.html about:blank
 skip-if(!asyncPan) != fixed-pos-scrolled-clip-layerize.html about:blank