I pressed buy for the 2 items and then started fight and mugged but turned out it showed me the loading sign for the second buy while I was attacking.
If I am in an attack, I am not allowed to buy stuff/ load other pages etc, so if my buy didn't already process due to lag, it shouldn't be waiting for my attack t finish to then process on server side. It should have returned an error that you cannot make this action while attacking someone.