I think its a memory issue in the maps. Most of the newer ones (past 3-4 years) give me that trouble. I notice if you just jump on to a map and log back out in a few minutes it closes no problem. If you stay in the arena for a while is gives that "stall" on closing. I seem to remember closing out the game because something came up and I walked away from my computer and when I came back it had finally closed out, but I might be remembering wrong. It only happened once.