VFW Cannon Breech wrongly modelled.
Rail (where the Cannon Breech move back after the shot), not part of it Cannon Breech componenet:
Spoiler
Stabiliser not a Cannon Breech componenet:
Gear/rack wheel not part of it vertical canon driver
Side lifts not part of it vertical canon driver
Lastly my point of view why it should be fix:
Spoiler
When the VFW gun breech not contain a lot of component (which needed) it eat shots without suffer any damage.
Basically if we take a look on different tanks/TD-s it looks like the previous mentined components as a part of cannon Breech and if one of them suffer a minor damage(like stabiliser ) a whole cannon breech destroyed(when take a shot) and not able to take a shot. Some examples:
