Loiter does not hold position

Hi, I have an odd problem:
The drone does not seem to try to hold the position in Loiter Mode, it reacts just as it would in altitude hold (slowly drifts away) , however the companion can fly a mission without problem so it is not related to GPS or Compass.

The exact same settings are used on a second drone that flies fine.
Does anyone have an idea what the problem is ?

OK nevermind, it seems it was caused by badly calibrated rc channels