User blog comment:Destroyer Maniac's Revenge/Trading ERROR????/@comment-98.80.35.252-20121216220424

The way I see it two things could have happened:

A) There was so much lag (and if you have been around a crowded GM u know what i mean) that the server read the trade twice and rejected the second one as it had already been completed

B)The GM tried to send you two items but since one item filled up your inventory, the second trade could not be completed

This is just my two cents worth, doesn't mean that it is absolutely true