Halfmarathon - PB on 21.1 no full race distance - what a mess ?

I have a problem. I run half marathons. Previously, my personal best was showing the entire course. It's obvious that it always shows over 21.1 km/h for the entire distance. However, it counted the entire race towards my personal best (as it did on the FR 965). Now, on the 970, it shows a personal best of 21.1 km/h during the race, not the entire race. What's going on? It's become a real mess.