I am pretty sure this is an exploit. I sold 241 robo crates for a weapon each, yet I have only 158 weapons. There are several offline trades that are exactly the same (431753, 431754, 431755, 431756 is one group of identical trades, 431771, 431774, 431775, 431776, 431777, 431778 is another) Each of the trades in the two groups were identical. In each trade, the customer received 10 robo crates, but I only received the 10 weapons on the first trade - after that, even though it was a different trade, I got nothing and they got the crates. They were all offline trades. Both times it was the same user. it happened a few times with other users in smaller amounts.

It does look like people taking advantage of steam API lag to do multiple request while the first one is still processing. We will investigate the issue.

I have sent you 65 crates and 1 ref in credit, please check. :)