Why do you press “lap” each length?

It’s only necessary if you rest every 50m.

If you don’t need to rest at this frequency, try a short 100m or 200m pressing lap only at the end of this interval. 
Not sure why the watch is losing…

Thank you, silentvoyager. I tried the distance correction on Strava as you suggested. The correction put us at 21 miles for the run (splitting the 2 mile discrepancy for the two watches). This correction is in line with your thought that the 6X tracks…

You might have just missed the badge by running too short.

40 miles is 64.37376

I would do a test and edit one of the runs and add a few meters to see if that helps. I've done a test with the 400 km biking badge and it worked to edit the distance and get…

Just tested it and it seems pretty much the same on a run. I tried the 1Hz data setting on the short walk back. It is still pretty much unusable cutting corners, meandering and passing through the middle of houses. I don't have a set route so I can't…

Sounds like you have that Display screen setup to display "Lap Distance" - you can go into the settings and configure the two customizeable screens.   Can change number of data fields displayed as well as change arrangement.  Recommend reading…