Definite steps to reproduce this issue:
1. get into hunter OR IFRIT with hmg or gmg,
2. move to gunner position.
3. while holding "lock or zoom" (right click or bound to any other key), activate the gun camera.
You will need to bind "lock or zoom" or "optics" in a way that allows you to press "optics" while already holding "lock or zoom".
Observe that gun cam is now zoomed in completely and can not be zoomed out.
Steps to fix:
1. Switch back to Gunners Seat again.
2. Switch to Drivers Seat. Your view is now normal again.