I was processing a bunch of Agerian Armor, and looking through my inventory while one failed over and over. I flipped to my pearl inventory and then it succeeded, with the next item in queue being my Valkyrie Treant Camo. I quickly canceled the processing.
I tried to recreate the bug, and was successful by having my pearl inventory open when the autoprocessing chooses its’ next target. https://i.imgur.com/Z2ggEil.jpg
It seems to pick a random cosmetic item from the Pearl Inventory to process. I don’t know if it will actually succeed, as I didn’t let it finish.