tracking problem

The past few weeks, NWA flight 781 from Minneapolis to Las Vegas, loses their tracking after about an hour in the air on flight aware. Does anyone know what the issue might be? I can get the arrival and departure times, on the NWA website, but I prefer to use Flight Aware.

It was working previously, but the last couple of weeks, the problem has been consistent. It doesn’t happen with the flight from Regan to Minn, just Minneapolis to Vegas.

This happens on some of the longer flights too if they are in the air for more than 3 hours.