Load windy.com, and zoom the map in and out with up/down scroll gestures on the trackpad. The map jumps around, seemingly using the wrong zoom origin.
Created attachment 411914 [details]
The issue is that when several animations for the same property targeting the same layer are added at the same time, we used to always override the previous animations and now, for transform animations, we actually use additivity over the previous animations.
Created attachment 411917 [details]
Comment on attachment 411917 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=411917&action=review
> + // animations created for a single KeyframeEffect, one for each trasnform component. In that
Committed r268771: <https://trac.webkit.org/changeset/268771>