There's a visual bug on oneui4 that I have only just picked up what causes it, and it may have been on older versions as well and I just didn't notice it.
When exiting an app, and then immediately clicking somewhere else on the screen while the animation is playing e.g. clicking on a folder, a weird effect happens when the app pops up again for a few frames
Additionally, another one I have noticed is where the continuing button from my tab s7 covers up the search feature, so I can't even search anything. This does not seem like a deliberate placement. Also it often isn't visible at all, so it takes me to an app instead of search.