There seems to be a visual error bug that makes it look like you can dupe an item. This has happened to me twice now, and I’m not positive what’s causing it.
The last time this happened I noted it was when I transitioned to a new area (in Temporal Sanctum this time) and while waiting for the load to complete I was messing with stuff in my inventory. I had clicked on an item and when the area finally fully loaded it the item popped out of my “hand” and back in my inventory and there appeared to be 2 of them.
The first time this happened it was with a unique and I do believe I was in the Temporal Sanctum that time as well.
This will be a hard one to show and may be a hard one for you to track down, but I wanted to bring it to your attention.
Thank you