Has there been any change in how syncing of really old devices work? I have two backup devices - the original vivomove and the vivoki. Both are paired to my phone but fail to sync - there is no error message, but the last synced date on Garmin Connect doesn't change. The vivomove is paired to Garmin Express via ANT stick and same issues is happening - sync "completes" but last synced date (and data) doesn't update on GC. Interestingly, settings do sync.
I have tried all the usual troubleshooting steps (reset device, unpair, re-pair...) but nothing helped. Since I am not using these devices frequently I am not sure when this started happening - the vivoki's last successful sync date was early July (according to GC).