Edge 520 Plus v 5.70 - Grade calculation

I was using firmware v5.50 and today upgraded to v5.70.

Previously the grade calculation worked with some delay (some seconds) and would always show 0% for slow speeds (more or less <7 km/h). But overall was fine.

With v5.70 it would still display 0% or other incorrect number even after finishing the climb. I did a climb that I know is 8-10% at 12 km/h and the unit showed 0-2% grade.

Can you guys at garmin fix functions without breaking others?