My average stride length seems to be calculating incorrectly. My cadence was 163, ran for 27:04 for 5km. That calculates out at 1.13m average, but Garmin Connect shows 1.02. I thought the Fenix 3 / HRM-Run was supposed to use reconciliation of the actual average stride length with the measured average to calibrate itself? This doesn't seem to happen as I get the same proportion of under-measurement of my treadmill runs.
I remember having this problem when I first got the Fenix 3, but a software update (either in the watch or Connect) fixed it. Seems to be broken again and I'm not sure when this started...