Gaps on heart rate and other info after 12. march 2021

Diamond said:

Is there something wrong with server or garmin connect android?

It does not look like, otherwise the user forum would be full of similar complaints. More likely either your syncing does not work correctly, or there is a problem with the storage or file corruption on your device.

In the first case, I'd recommend  checking out the Device Sync Audit (in GC Mobile Menu » Settins), after such incident. Also use the navigation button at the bottom to see more than just the last screen. And watch for errors, warnings, or other suspicious text.

You can also check the tips in the Sync / Connection Troubleshooting Guide, in the case the syncing does not work reliably.

In the second case, check out how much free storage there is on the watch. Also verify whether in the folder //GARMIN/Monitoring are not some older files. The monitoring  contain the HR, Steps, Calories, IM,... data for the period since the last syncing, and upon sucessfull syncing they are being deleted. 

And even if there is sufficient space on the storage, delete all files from the folder //GARMIN/Activity/. If there is an old broken activity file, it may be causing havoc during the sync attempts

There is this log entry at the time gap ends. After this sync next sync is successful. That Device Sync Audit log does not go back to 12. day when this started. But this is for example 15. day gap:

Upload Status: NOT_STARTED,
Download Status: NOT_STARTED
Time Sync Status: SUCCESSFUL
Overall Sync Status: SUCCESSFUL

No old files in Monitoring folder and there are plenty of space in device.

I'll try that troubleshooting guide, thank you for advice.