There is a glitch I've ran into a few times where the weapon that I trying to trade another weapon for is kept, and a weapon is have put away it traded instead.For example, lets say I have Weapon A out, Weapon B for my secondary, and I want to buy weapon C. Sometimes, even though I have Weapon A out, when I go it buy Weapon C, it gets rid of Weapon B for it, so I end up with Weapon A and C, rather than what I wanted, Weapon B and C.