The REPO is a small mission done in Eden editor:
1 - I added a player with edited gear (bergen backpack, etc).
2 - On the player init code i create a weapon holder on his foot and add 2 balaclavas to it.
When you play the mission and change the balaclavas in the face gear slot, one of them dissapears.
1 - Run the anexed mission in single player.
2 - Get one of the balaclavas on the ground and assign it in the face gear slot.
3 - Right click in the other balaclava on the ground.
4 - The assigned balaclava will dissapears.
If you remove some of the items from the backpack and the vest (making them half empty), the bug not happens.