It was the mistake of the CSP as suspected on this tweet: https://twitter.com/ncbrady/status/1324269514259943424. So the CSP did something wrong (although autopilot deployment still worked). I hope he can fix it for the already delivered devices.
On the one hand I'm happy that it finally works and that I didn't make a mistake and on the other hand I'm frustrated because I lost dozens of hours.
Thanks to everyone who answered and helped here...