diff --git a/css/css-anchor-position/META.yml b/css/css-anchor-position/META.yml
index e567484c3..26a2c796b 100644
--- a/css/css-anchor-position/META.yml
+++ b/css/css-anchor-position/META.yml
@@ -4529,3 +4529,8 @@ links:
       at (1.5) should be [flip-block]'
     test: property-interpolations.html
   url: https://bugzilla.mozilla.org/show_bug.cgi?id=1911925
+- product: firefox
+  results:
+  - subtest: anchor-scope scopes to the flat tree
+    test: anchor-scope-shadow-flat-tree.html
+  url: https://bugzilla.mozilla.org/show_bug.cgi?id=1920495