TRUE (f...) UP in body battery

I am a garmin fan (have the badge) and have been using fenix by day and vivosmart by night for years. Just switched from fenix5/vivosmart4 to fenix7/vivosmart5. With true up I expect data to be interpreted in the same way by the two wareables. But no. When I switch wareable the body batt f...s up. How hard can it be? Please fix this, thank you.

Best, Morten