Using a build based on r282272: Load https://blog.cheapism.com/imperfect-foods-test/ (reproducible with cleared website data or in a private browsing window) Scroll the page. Most of the page appears blank and stays that way for a long time, and the scroll position keeps getting reset. Reloading the page eventually shows all of the content. In Chrome it loads and renders faster.
Sounds like a hangy web process. Got a sample?
<rdar://problem/83627904>