I wanted to keep this going in the new forum as qinzuoqiu may have found the cause, its certainly worth investigating further.
Copy of his post from the old forum:
“Actually, i found someting new about this bug, also happend when i use british: sometimes, once weapon is damaged(white health bar is not full), then the weapon cant be deploy properly, include HMG and mortar.”
Olhausen and I ran several tests to see if we could replicate the stuck HMG bug by damaging the weapon as suggested but unfortunately we couldn’t get it to happen. HMG was crewed properly every time. It is the most annoying bug as it only happens very rarely but is very frustrating when it does. We will keep searching for a fix
see the difference on the circles arround the mgs? US one looks like a standard weapon in the same class like a bazooka or a light mg, the German one has a different circle, it has kinda a circle seperated with arrows pointing to the inside (like other things you can crew)