Just tested on iOS 17 beta 4 (developer) and discourse UI seems broken. (Safari and Chrome)
It seems as though the scrolling makes css changes and jumps.
it seems the issue is with borders I’m pretty sure.
.nav-pills>li.active>a are changing size as you scroll which causes all content to “jump”.
I’m not sure if it’s a padding issue because it seems like the border-radius is being maintained. But my assumptions is that it’s either a padding or borders issue?
This appears to be happening on other themes too, with this padding shift causing jumps.
Here’s a quick video :