What is the glitch?
Permanently stuck as waiting within the waitspawn, even when the game has started or mobs have been released

What causes the glitch? / How can I re-create the glitch?
Log in before the game starts, so that you're a waiting, but then log out before the game actually starts. If you log in after the game starts, you are stuck as a waiting without any way to switch out.

How common is the glitch?
Way too common. Used to occur on old DVZ as well.

How many times have you seen the glitch?
Only once, but I've only played two real games. It used to occur a lot in the old DVZ as well; I've done it myself 10 or so times there and seen it more times.