I have Garmin Mobile Connect (3.19.0.0) on my Microsoft Lumia 950 (Latest production release, not fast ring or anything silly).
Quite a few times recently when I sync with my watch (Garmin Forerunner 230, Firmware 7.30) my steps are being synced correctly, but any running activity is not being downloaded.
I have tried rebooting both phone and watch, deleted and reinstalled Garmin app, removed device from Bluetooth and re-paired. Sometimes it starts working again but then my next run doesn't sync.
If I connect my watch via USB to my computer the activity syncs fine, and is uploaded.
Anyone any ideas? Are there any known issues with the latest firmware?