The forestry backpacks delete all their inventory when their dropped on the ground or put into a chest
It hasn't been doing it lately for me either but ask anyone who is a Gangbanger, it happened A LOT in the beginning of alice.
May have been fixed with the forge update aswell. I made sure to try it multiple times yesterday. The bags do behave a bit strange when flipping them around with InvTweaks, but they save their stuff properly.
Yeah, invtweaks + mod items = crap. If you want to sort your inventory, place any item that won't sort in your hotbar and it should work fine. Items that don't sort are things like backpacks, eu-readers, etc. If everyone can make a list of the things they find that don't sort right, that would be awesome
