Edge 1040 losing its mind

I have an Edge 1040.Latley it has been acting very strange.

2 weeks ago, while riding it was stuck at 16 MPH andonly change when I stopped.

Last night we did a ride.  When finished it said the ride was 25 miles in distance.  Everyone else was recordting ~20 miles.  I checked Strava and Connect.Garmin and both recorded 25 miles.  I exported the ride from Strava into RWGPS and that showed the correct millage.

Any ideas what is gong on?

Thanks

Ron