Like the title says the initial minute or so moving forward makes the copter go straight north-east 45degree heading not 0degree.
After a minute or so this corrects itself
From the logs i see
EKF2 IMU0 ground mag anomolly and EKF2 IMU1 ground mag anomolly
followed by
EKF2 IMU0 in-flight Yaw alignment complete and EKF2 IMU1 in-flight Yaw alignment complete.
I’ve re-calibrated compass a couple of times a good 20m away from a nearby tin roofed shed in a field ( should i go even further?)
I ran a compass motor calibration (should I do this with an external compass) It may be down to this calibration, how do i delete?
log available here. https://1drv.ms/u/s!AtWZQxEqLM0Hg_MZYj6-O5r4iXimkQ