Seeing Friends' Masteries Instead of Your Own

If you get into queue, kill time by viewing a friend's profile, go to their masteries, and get called into champion selection, then the list of mastery sets will be that of your friend that you were viewing. You will be unable to select your masteries, and you'll end up with the same ones that you had equipped for your last game.

Not a major bug, but still noteworthy, IMO.