Now it stays stable for the first 5 - 10sec. and starts circulating again. I made a Video of it too but I can’t upload it here so if you want to see just download from my cloud: https://www.hidrive.strato.com/lnk/jk4MJwmd
It would be nice if someone could give me a general hint why this behaviour appears.
In Local Position x and y I can see clear a unstable oscilation, but I tuned my PID already and the problem still occurs.
Does someone has another hint?