Created attachment 347085 [details] HTML file for reduced test case Steps to reproduce the problem: 1. Open index.html Page Attached 2.A. Click on "<" or ">" to initiate CSS transition / transform 2.B. Or on Mobile touchmove along the lettered elements to initiate CSS transition / transform What is the expected behavior? The expected behavior is a smooth transition of the lettered elements. What went wrong? The transition occurs but it is not smooth. See video for jitter reproduction. Did this work before? N/A Does this work in other browsers? Yes Video reference: https://drive.google.com/open?id=1XpZ1f7_A6c2jytFJ0rwM4lFAYmHl9Ng4
This doesn't reproduce with the Web Animations flags on, which is a good thing :) This can be verified with a Safari Technology Preview build.