Just did a shakedown flight on my new P4 in the same area as I have flown the P3A.
There were no issues with the compass, GPS, no switching to and from GPS mode , it just worked as it should. I will get some more flights in today and tomorrow to get a better data set.
I am itching to upgrade the firmware, but I want to get a benchmark on how it flys right out of the box before I upgrade.
The P3A (now returned as defective) logged 14 flights and only 2 did not have the compass errors. These were all in the same location (my (very rural) residence lol) as today's test.
So far so good, but until I get some more flights in, I am not calling this issue solved.