Sometimes the ticket will get stuck on the screen, probably a display bug only as you can't click it
I'm not sure, I was doing a loop of buying bunch of tickets and opening them back to back (this was before the scanner). At some point one of them didn't leave the screen, it doesn't have a discard or claim button, and it also blocks the next ticket's discard or claim button partially (need to find the proper spot to click instead of the whole button working). I played some more and I'm not sure if it was because I was using the scanner or that I was spamming the 3rd game forward, but it didn't happen anymore after that point.
So maybe something with the slower drawing process with back to back tickets?