A little update on the situation. Had a friend over who has a p2 himself and he had a different technique in doing the calibration. He did not spin the bird in the same spot as i have done but he stood in the same spot and spun it around himself with his arm almost straight. Then he repeated the same process with nose tilted down. Question is, is that the right method or not? The app also asked me to calibrate the rc, wich i had not done before either. Worth to mention that we were in a different location too, all the calibrations were done there offcourse. The bird flew perfectly, no problems with anything at all. Interested of what happends in the future and how the bird reacts from revisiting the place where problems occured. Who knows, the soil might be rich of iron as mentioned in other replies. Thanks all for the help!