I have recognized a few minor bugs on the German mobile AAs. The hitmakers do not appear to work (SdKfz 7 with Flakvierling and possibly the Opel Blitz - Flak 38)
Another bug on the Opel Blitz with Flak 38: Everytime you switch seats from the gun back to driverseat, the gun gets reoriented to the forward looking positions. This is pretty anoying, if you are just doing some minor repositioning and have to turn the complete gun again.