Failing WPT. Our behavior matches blink https://wpt.fyi/results/css/css-flexbox/abspos/flex-abspos-staticpos-fallback-align-content-001.html?label=master&label=experimental&product=chrome&product=firefox&product=safari&aligned&q=label%3Ainterop-2021-flexbox There's some discussion/debate going on about how to interpret the spec and how to resolve a possible conflict between two CSS modules. https://github.com/w3c/csswg-drafts/issues/5843
<rdar://problem/95389151>