[edit: not sure if already reported, but here goes...]
On the He111 in the #2 and #7 (nose and "forward gondola") positions, the head movement is scaled differently, so that there is almost no movement up down left or right. It does move extremely slowly over a short distance, in all directions, so I assume there is some kind of head movement scaling bug that just shrinks it all down.
These are the 2 positions that can load the 20mm MG/FF cannons, perhaps that is causing it? Regardless, the bug persists even if you load the 7.9mm MG option.
All other head positions move around just fine. Only these 2 positions are bugged. Repeatable offline every time.