I think I’ve been having this issue for over half a year now, and it makes phone capture impossible or frustrating.
Previously, before the gpx update and even a couple of versions prior to that, the only issues with image headings I would have would be due to the magnetometer itself being wonky, metal interference or old calibration. This was quite rare and I could just walk around in Manual mode turning the phone in different directions and the photos would almost always have the correct heading.
Then something happened, and image heading got absolutely broken. It would show correctly during capture (presumably due to iOS compass data being shows), but then the actual heading on upload would be 90-100deg off. I’ve tried debugging this together with mapillary support, and you might remember iOS app releases claiming to fix the issues.
Decided to try out the latest version today, and indeed there doesn’t seem to be that much of an error, however the heading is still +/- 40deg on some images. On some, it would seem it is interpolated from the gpx track rather then the compass. An image captured in the same position could have heading variances of 30-40deg, with the phone held still.
Am I the only one having this?