Playing a private modpacks with some other people. And someone noticed that if you have a backpack in the backpack slot from curious mod + chestplate on your player's armor slot + 1 more backpack in the inventory slots and then die. The Totem of holding appears as usual, but when punching him to receive items back, it will void one of the backpacks. Presumably it tries to put both backpacks on the back slots from curious, ending up overwriting one.

are you playing with quark 4.0-438? I assume this is with backpacks from sophisticated backpacks? if so I can't reproduce this with only the backpack mod and quark

Oh my bad. I checked the changelogs but accidentally missed the note on the fix. Will update the mod. Thanks!