PS4: Trade abandoned with error - offered item duplicated in inventory

[(PSN)coma-edge]

During a trade I offered a mod in return for platinum and received the following message: "The trade failed. Your trade partner no longer has the amount of platinum offered to you in the trade." However, the other player claims that he now has the offered mod in his collection. I did not loose my copy of the mod and my total platinum remains the same. I've never encountered this error message before and am quite puzzled.