Early Dash FW uses instantaneous speed data to calculate distance. This can result in poor speed values, especially in tree cover. When uploading to strava, the GPS track will match, but distance can be a lot shorter than the actual distance traveled. To update the ride to use the GPS based distance and correct the data, click "Distance (?)" beneath the ride distance and select "Correct Distance". Strava will update within seconds to the correct distance.

This can be done on any ride, regardless of Dash FW used. Note that this will not always make the ride longer, but should fix most customer reported distance discrepancies. 

Note: Dash's distance calculation was updated to track distance based on GPS alone, however current files (as of 1/11/18) coming through Stages Link are still using speed based distance accumulation and can possibly see discrepancies here.