It seems that x-axis of time is not linear, the timesteps are for example 0:00 - 13:11 - 32:36 - 49:31 and so on. How could anyone read that chart correctly if timesteps are random on linear chart???
I have the same issue. I cannot make sense of the X axis at all. It's not linear time. I am pretty sure it's not distance either (out and back rides would look symmetrical) Ideally, it would be nice to have it user selectable (linear time, or distance).
But there is a new bug with garmin coach laps, those are broken in diagram. 
