Stuck on a distance screen with constant vibration when starting a run exercise

Hi - when I press the start button to start a run, my watch is stuck on a screen that shows 0.0 with a little compass icon on top. The watch keeps vibrating with a half-a-second pause every 5 seconds. The only way to stop or get out of this is to press the start/stop button to stop the run, then the usual stop menu comes up and the watch no longer vibrates.

This is the first time I tried to use the run exercise after the watch was stuch in the boot loop 7 days ago and subsequently fixed. 

Other exercise modes seem fine. In the end, I had to use the walk exercise to record my run but obviously it records less data than a run exercise.