Well, this once happened when I was playing true_fort
I was defending the intel as an engineer, when this guy called thedude planted a sentry on a wayout. The only problem is that somehow there was two sentries at once, not one. I mean, there was one shooting but another one seemed to be stuck in eachother.
Me, a pyro, a spy, and a deto were attacking it like crazy, until one minute of attack, when it finally explode.
I am wondering; is this a cheat? An exploit? Simple bug or glitch? Has it happened to you before?