In the timer auto-pause settings, it does not allow you to set a speed lower than 1.6 km/h when you select custom speed.
I don't understand your answer, but if it is a problem, when you are on a route and going up a steep slope, even though you are certainly going faster than 1.6 km/h, the system must not measure the speed correctly and then the activity is paused, so it does not record distance and ascent during that time.