The first problem sometimnes happens when the device turns on and the tracklog is automatically start but device only count/save the time and doesn't save the GPS coordinates. Device reported a GPS accuracy of 3 meters the whole time.
But more often problem is that the device freezes in the middle of the trek/trip/activity and stops recording the route/data.
When the device freezes, there are two scenarios:
1. After pressing the any button, the device restarts itself and continues recording the tracklog.
2. The device doesn't respond to button presses, when the On/Off button is held approx. 15 seconds, the device turns off, then the device needs to be turned on again and after turning on, it continues recording the tracklog.
In both cases, data from the time of freezing are missing.
In all cases I had the map screen and active navigation to waypoint.
I reported the problem to Garmin support.
Garmin support answer
Please turn off auto track by going into settings> recording> auto track> off.
As for the second issue, please refer to this article for troubleshooting: Garmin Outdoor Device Freezes, Reboots, or Will Not Fully Power On
As for the second issue, please refer to this article for troubleshooting: Garmin Outdoor Device Freezes, Reboots, or Will Not Fully Power On
So I wrote back...
I have to praise Garmin support, they respond very quickly and try to help.