Had this bug once on Santa's workshop and one more time on one of the older maps. Tragic Kingdom I think. When using the shop after a wave, the 9mm simply vanished from both, the loadout in the shop and my weapons selection. I could not select it, I could not buy ammo for it. It reappeared after I died and respawned and I would assume buying a second 9mm would also work, but the bug seems to occur regularly. Had other people on the server complaining about weapon disappearence as well.
