In some instances the interface for scrolling through perks shows the perks which should normally scroll out of the vision on top of the display. It happens to me during combat. The problem doesn't persist when going back to the base.
How to reproduce: Start battle and alt+tab from the game. When I go back and open the perks interface from the char. sheet, it will reproduce the problem in the subsection where there is more perks than the perk window can display. Perhaps it also requires some time in the battle, but the former seems reproduce for me. In case it plays a role I'm using the linux build v14.
Seeing there are several graphical glitches when redrawing the screen or display elements during combat, my very wild guess is that it's somehow related. I don't know yet how to consistently reproduce all of them but it's usually when I go out of the main combat screen either into inventory view or out of game (alt+tab) and back. For example, sometimes the game keeps a tooltip element on top for some time even when the mouse is already somewhere else. Or often the AP circles don't seem to update when going into inventory or changing weapons, but something similar was already reported before. All of those glitches usually go away in time.