Tracking Functionality

I have been tracking my son with a new Mini 2, and it was putting points on the map every 20 minutes as we set it up. At two points when he was stopped for a long period of time, however, it stopped sending points at least that I could see. In other words, where he stopped for the night, I can see perhaps three points/times for the whole night, and the following day when he was stopped and in one area for 8 hours, I got perhaps two points on the map and I started to wonder whether it was no longer tracking properly until I got another point nearby much later in the day. Is this normal? Am I just not seeing all the points on the map because they're so close to one another? Or is it not functioning correctly?