I felt the same way on mine, which was basically stuck on 46 ( since I got it late march) but where I run isn't a flat rod and has many hills so many that was why it wasn't updating. Anyway I stopped doing any workout/running for 6 days (uni finals and got many assessment due)... Lo and behold my Vo2 max dropped to 45 😅. Anyway just got the hrm tri 3 weeks ago and we'll see if it updates then. But I don't think your vo2 max will update often unless you drastic improve on your running time/performance.
My Vo2Max is quite different. It wiggles between 58 and 60 a lot during a month. Looking at the VO2Max report for the last 4 weeks it shows 60, 58, 59, 60.
