While hiking from times to times - the position arrow gets stuck when following a route/course. I think once it even happened without active route/activity/course.
While navigating then the navigation will continue but route back to the stuck position. Especially if you are in an area with bad map quality, this is super annoying and I got lost a couple of times due to not noticing that the map was stuck.
Only solution to correct - pause activity, reboot, resume activity. Sometimes pausing/resuming activity alone solved it too. This happened with the screen lock on or off.