Pace and Time error

Maybe you have different settings on the watch or your friend ran better positioned for getting a good satellite reception. 

MovingTime, Speed and Pace Calculations

Supposedly, when you use running activities, accelerometers are used to detect motion and rest (instead of GPS in cycling activities), but later they say:

“ When uploading runs, ….. If you do not pause at all, our server will calculate moving time-based on the recorded GPS data. Again, even though elapsed time may be the same, Strava may calculate moving time differently than other platforms.” So ultimately, even if they have readings from accelerometers about running motion, they still mix GPS in, if not use GPS alone. GPS drift alone can mess up max speed (as mentioned in the last section), producing different values.

So fully agree with ​@Jan_Mantau on this. And unfortunately, even with good settings, it’s not on you how to get good reception, it’s an air transmitted wave ultimately, so interference is always an issue. That said, I remember I had inconsistent readings when I had set my phone’s settings for the recording app to stop it from running in background. It wouldn’t even show a map that way. GPS draws more battery power, but without it, no GPS map (iirc).