pretty self explanatory

To Reproduce:
Install curios and this mod.
open curios inventory with the button
shift click a backpack into that from your main inventory

Expected behavior:
backpack get shifted to Back curio slot, game doesn't crash

Mod version:
3.0.3.297
curios version:
4.0.5.2

I will need the crash log for that

So the shift clicking into backpack works for me and I am sure for a lot of other people given how many download the mod and how common it is to have curios in modpacks.
which means in your case something special is happening but to understand that better I need the crash log, otherwise I can just close the ticket

closing as no additional info was provided and just shift clicking into curios slot works in many different packs