Return of Reckoning

It happens only on my chosen Kriegg:

The quest is complete, whenever I try to collect the gold (and the Medallions!!) I receive this message:


Any other with the same problem, and maybe a solution? My backpack has enough place, I still loot and roll items with no advices. Plus, I do not have salvaging.

I used to have a similar problem, and mine was caused by the "sorting mechanism" in bags, that I had enabled. When I disabled it, the problem didn't occur again.