I'm looking at a workout that I did indoors on my rollers.
Computer is the 705 with no speed sensor, GPS turned off. So all it's recording is power, cadence and HR.
Golden Cheetah's analysis is based on speed. Which means it only looks at data where v>0.
You do the math.
edit: On second glance, I'm not sure what's going on. I looked at my commute home, with the GPS on and plenty of speed/distance data, and for my 1hr41min ride, it says my "Time Riding" is only 20 minutes. wtf?