I have a curios that gives extra back slot (+3). I wear that, a backpack and another curios in those back slots. Whenever I log in or /reload, the backpack and the other curios pop into my inventory. Only the curios that gives extra back slot remains in the main back slot. I didn't happen in the previous version (9.2.2). Only happen since I updated to Curios 9.2.3. I have other curios that give slots too but only the back one having problem.

What item exactly is the curio that gives extra back slots and what mod is it from?