Since Edge 530 v4.10 the compass is randomly rotating when using custom data fields from the Connect IQ Store e.g.
- SPH Graph (https://apps.garmin.com/en-US/apps/d4e267ad-c860-44e6-9686-18cbca037ab0)
- MY EDGE2 (https://apps.garmin.com/en-US/apps/612e0b7a-ac48-47b3-8718-a8f66109ab90)
The standard Garmin compass data field is working as intended.
The author of SPH Graph told me that this is caused by the garmin library which custom data fields must access to get the compass data. These custom data fields worked flawlessly before the v4.10 patch.