The crash dump is at least pointing to the same place which have caused the weaponless armory/stash interaction crashes, so chances are that one has become fixed in my dev build but I do want to verify it.
I'm trying to follow the procedure to reproduce the bug, correct me where I'm going wrong!

1. Start a single player quick match, I went Keepsake Bay
2. Press esc to enter the background game and go to an armory
3. Pick one riot shield (tap LMB to equip) and two sandbags (RMB to backpack)
4. Leave armory, access inventory and equip sandbags from backpack (with LMB) (I have 4k XP so my equipment slot allows me to have 2 sandbags, it's 2/2 now), no sandbags are left in backpack
5. Switch to secondary weapon which takes the sandbag in hands, deploy the sandbag, now I've got 1 sandbag left in hands, none in backpack
6. Dropping sandbag on ground leaves none in my equipment, one on ground
That at least goes as expected.