Apple Watch 6 doesn’t log walking minutes

I have an Apple Watch series 6. When I do an indoor or outdoor walk it doesn’t log all the minutes to my exercise ring eg 30mins logs 16m. It logs the kcals but not the time. I have reset / recalibrated and followed the instructions online but doesn’t work. I think this is just a bug in the watch? Anyone know how to fix this or do apple need to update its software ? It’s annoying to go out for a 60m walk and it logs half that time. Meaning my exercise ring stats are wrong.