Fenix 7 cycling distance error - jumps to 8300+ km after a few minutes of riding

I've been getting an error where my cycling distance jumps to 8300+km after a short time (it should be about 22km for this route).  For some reason it's always around 8300km.  The other data points - time, speed etc are good but the distance is wildly off.  If I stop the activity and immediately restart, it will record distance normally.  The watch is 7 months old and used to measure this route acurately but this problem is coming up more and more and now it happens almost every ride.  I frequently ride the same trail out and back and it almost always happens on the way out but never on the way back.  Any suggestions?  

I have tried:

Updating to the latest firmware

Waiting for a few minutes after it shows the GPS being connected before starting my ride

Starting the GPS a bit farther down the road from my normal spot

Cycling the watch power off / on 

Thanks for any help you can provide.