V02 max has plummeted after the update

Just updated to new software (sorry don't recall version) and my V02 max reading is now utter rubbish. It's dropped randomly by 4 or so point, based on a treadmill run done 2 weeks ago. 

Treadmill runs don't affect V02 max as it needs the GPS. My stats are now all mucked up, and they were absolutely normal before the update.

I had huge issues with a vivoactive 5 that I returned and bought my 165 music instead. Please stop breaking our watches with updates!