https://codepen.io/damianmuti/pen/MvYPPa Compare Safari and Chrome or FF. In Safari, the image have odd horizontal sizing issues, and you don't see any of the motion blur effect.
Possibly related to using a drop-shadow filter on compositing layers.
I am able to reproduce this issue in Safari 15.5 / Safari Technical Preview on macOS 12.4, where the animation / motion does not work similar (kind of phasing out while blurring out) compared to other browsers (Chrome Canary 105 and Firefox Nightly 104). Thanks!
<rdar://problem/97203719>