I had a fun bug that just happened to me: I was looking at a PDF, and by default I have "continuous" turned of. However it was too small so I hit the "zoom in" button. Then at every interaction (moving the mouse, for instance), the PDF started getting smaller. This kept happening even if I right clicked and chose "continuous".
Now it's happening with all my PDFs without changing anything (as if they all shared the same zoom setting).
Quitting and relauching did not help.