I can't believe that I'm the only one to notice this. Every activity I've looked at has issues with the heart rate graph. The first 2-4 minutes of the activities show a flat line and the same value or a slight slope in the graph but still the same value. Doesn't matter if I have it set to time or distance. It shows the same issue at the top of the page in "Classic GC" in their ad for "Modern GC". It's also on DCRainmakers review for the FR920XT. Happens on activities from my Edge 810, FR910XT and others.
No issues with this when viewing activities in Classic GC.
Flat Line...
Sloped Line...
Top of Classic GC...
DC Rainmaker's 920 review...