Forum:Inventory dissapeared

I was playing with a friend online. He was a level 20 hunter and I was a 58. I was sitting on the turret during the fight against the first major boss for the first vault piece. when I got off the turret when krom was killed I went into my inventory to look at my weapons that I could soon equip and everything in y inventory except what was equiped dissapeared. Come to find out the exact same thing happened to my friend as well. what would cause that.

P.S. we could still pick up new gear and it would stay in the inventory.