230106 2021-09-09 10:04:13 -0700 Safari Transitions No Longer Convert Between px and % 2021-09-10 02:13:47 -0700 1 1 1 Unclassified WebKit Animations Other iPhone / iPad Other RESOLVED DUPLICATE 228811 InRadar P2 Normal --- 1 matt graouts dino graouts koivisto simon.fraser webkit-bug-importer zalan oldest_to_newest 1791949 0 matt 2021-09-09 10:04:13 -0700 This is iOS 15 beta 8 Safari This CSS code previously worked, where adding a class to start the transition would animate from 100% to 0px. transition: top 0.25s; top: 100%; html.active { top: 0px; } The above has stopped working in iOS 15 Safari Beta 8, but the below works, replacing the px with % transition: top 0.25s; top: 100%; html.active { top: 0%; } 1791962 1 webkit-bug-importer 2021-09-09 10:30:38 -0700 <rdar://problem/82932304> 1792010 2 graouts 2021-09-09 11:45:01 -0700 Matthew, when you say "stopped working in iOS 15 Safari Beta 8", do you mean it worked in previous beta seeds of iOS 15, or just iOS 14? Thanks. 1792011 3 matt 2021-09-09 11:50:32 -0700 Stopped working between iOS 14 and iOS 15 beta 8. It was not tested in any other betas. 1792023 4 matt 2021-09-09 12:15:15 -0700 iOS 14.4 to be exact 1792024 5 graouts 2021-09-09 12:18:55 -0700 Oh, I think this is a duplicate of bug 228811. 1792026 6 graouts 2021-09-09 12:25:08 -0700 *** This bug has been marked as a duplicate of bug 228811 *** 1792029 7 matt 2021-09-09 12:26:55 -0700 I will check tomorrow as my app also animates widths on some progress bars and so should fail on those aswell. Tested in iOS back to 12.4 and it is fine in those versions. 1792279 8 matt 2021-09-10 02:13:47 -0700 The other transitions work fine in iOS 15 beta 8 and so yes it seems to be a duplicate of https://bugs.webkit.org/show_bug.cgi?id=228811 Thanks for the help