Beyond hover detection causing the app to preload (TIL that's apparently a thing? Can anyone confirm?), another case I've seen is trying to slide up to unlock but accidentally triggering the lock screen camera for a millisecond or two, which also causes the indicator to linger for a few seconds.
edit: Is this actual "hover without touching screen", which is what I was shocked about, or is this more like "finger passes over the icon while swiping between pages"?