diff --git a/testing/web-platform/meta/scroll-animations/css/animation-shorthand.html.ini b/testing/web-platform/meta/scroll-animations/css/animation-shorthand.html.ini
index df564bc9ddfc..055c4aa03203 100644
--- a/testing/web-platform/meta/scroll-animations/css/animation-shorthand.html.ini
+++ b/testing/web-platform/meta/scroll-animations/css/animation-shorthand.html.ini
@@ -7,7 +7,7 @@
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1824261
     expected: FAIL
 
-  [e.style['animation'\] = "1s linear 1s 2 reverse forwards paused anim timeline" should not set the property value]
+  [e.style['animation'\] = "1s linear 1s 2 reverse forwards paused anim --timeline" should not set the property value]
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1824261
     expected: FAIL
 
diff --git a/testing/web-platform/tests/scroll-animations/css/animation-shorthand.html b/testing/web-platform/tests/scroll-animations/css/animation-shorthand.html
index cb63137f5c95..b128b33dd8b2 100644
--- a/testing/web-platform/tests/scroll-animations/css/animation-shorthand.html
+++ b/testing/web-platform/tests/scroll-animations/css/animation-shorthand.html
@@ -20,7 +20,7 @@ test_invalid_value('animation',
 test_invalid_value('animation',
   '1s linear 1s 2 reverse forwards paused anim view()');
 test_invalid_value('animation',
-  '1s linear 1s 2 reverse forwards paused anim timeline');
+  '1s linear 1s 2 reverse forwards paused anim --timeline');
 
 test_computed_value('animation',
   '1s linear 1s 2 reverse forwards paused anim');