1. Equip binoculars in hand ('B' key by default)
2. Board a vehicle on the gunner sit
3. You will experience a bug related to the vehicle type as described in description

• Uncommon quickfix n°1 is to fire a round by pressing the fire key (left mouse button by default) that actually executes the "put away binoculars" action at the same time)
• Uncommon quickfix n°2 is actually to disembark, then unequip from hands binoculars and get back as gunner into the vehicle.

I've selected major severity, because :

• Each time a teammate boards a vehicle with me as gunner. I need multiples minutes to explain him all bugs that might happen and all missing features.
• I kill all the time people who seem having this bug and who don't shoot me back or who can't aim.
• You can't imagine how many lives this bug saved when I was driving a BTR on conflict and my gunner had this bug.

Important : There might be another thing without binoculars that recreates the same bug with the BTR on multiplayer server but I have not been able to reproduce the issue so far.