I got an error saying “Does not fit in inventory” even though my inventory was empty. I looked online and one suggestion had been to move an equipped item into the inventory to refresh it. When I put my belt into the inventory, at first nothing happened. Then I picked up a unique amulet off the ground and suddenly my 2LP Legendary belt became an arena key with a legendary border. This occured while playing in online mode and inside one of the new cemetery echoes.
Screenshot: https://imgur.com/a/uXMc6R0
Player.log (3.7 MB)