KF drift and yaw resets on Pixhawk-4 using Ardu 4.0.5

Hi Forum!

I am having many issues after installation of PX4 4.0.5 on Pixhawk-4 + F9P H RTK module from Holybro. Main issues are EKF drifts that result in ekf_yaw_reset and switch to “land” mode + uncontrolled yaw motion.

Issues happen on multiple drones and sporadically, i.e. same drones may fly perfect and next day display the above. I am having trouble starting the debug process here. I was thinking of throttle vs mag interference issues (arduo doc on mag interference) but can probably be many other reasons.

I was hoping to get a pointer to start of. If anyone can help on the above experience with the configuration described - it would be great!
Tnx