Looking over the track I can see that your device was showing the most part. This would usually mean that the GPS Fix was lost and only regained when you can see that the device is showing it properly again.
GPS Fix can be lost when you enter any building as the GPS signal can not penetrate the structure.
Could you please clarify whether you were passing a tunnel or a building of some sort?
I would also suggest going to SYSTEM settings on Configurator and using the "After Position Fix" under "Records Saving/Sending without TS" and enabling "GNSS Fix Holdout". This would make the track more accurate and clear to see where GPS Fix was lost and found again.