When I ballistic scroll to the bottom of the editor while focused, the editor scrolls up once I hit bottom, evidently to make room for showing any meta boxes beneath the editor in the event of an unfocus. The mouse ends up exiting and reentering the editor when the elastic bounce back animation does its thing. This causes an unfocus/focus flicker. It’s pretty annoying when you’re moving up and down a document a lot. Perhaps not a common flow, but one I get into all the time when doing live note taking for the dev meetings.
Note also that the editor controls shift down a bit when scroll reaches the bottom, leaving a strip of white space above the controls.