I'm currently using the Backpacked mod, and after my character dies and retrieves the grave, the backpack doesn't return to the proper slot. It will be placed instead in an empty inventory slot. The backpack should have contents before dying.

Steps to replicate:

• Wear backpack from Backpacked mod
• Put items inside the backpack
• Die by any means with the backpack still on
• Go and retrieve the grave

Seems this happens because backpacked is saying "this item can not be unequipped", and yigd sees this as "you will never be able to take this item off your body until you die" (like curse of binding). So to stop this from happening, the backpack will be placed in your inventory instead.
You can disable the treatBindingCurse config as a temporary fix, while I look for a better solution the issue (do note this will cause curse of binding armor to get stuck to you, even when you die)

Or disable the backpacked lockIntoSlot config. That would work too