imported/w3c/web-platform-tests/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-overflow.html is failing because the 'actual' result image has a transparent area that should be opaque white (it otherwise matches the expected image). I assume this is happening because the fieldset area that overlaps this transparent area is being treated as an opaque rectangle, when its actual opaque area is determined by its children. This bug almost certainly isn't WPE-specific, but only WPE has async overflow scrolling enabled for all tests.
Created attachment 432935 [details]
Created attachment 432936 [details]
Created attachment 432937 [details]
Committed r279640 (239454@main): <https://commits.webkit.org/239454@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 432937 [details].