Fenix 3 - gives twice the distance in Garmin Connect

[sbarrett]

I have a competitor in our club who uses a Garmin Fenix 3. When he run with MapRunG, the distance shown in Garmin Connect, of his run is about twice the real length of the run. Any having the same problem, and how did you solve it?

[MichaelRaz]

Used to have a Fenix 3 and, although not the most accurate GPS watch, I don't see how this could be related directly to MapRunG as the app just uses the normal tracking/GPS base (with punch information overlaid in the fit file - look at the results in Garmin Connect and you will see the lap information is based on punch location/times).  Have you looked at the actual track showing in Garmin Connect or pulled the fit or GPX file from Garmin Connect and looked at it?  

If I was to hazard a guess... The watch and Connect consider the Maprun as a normal activity so as soon as you press "go to start" this activates the activity as if it was a run/hike/whatever, including distance and time.  Same at the end - when MapRun punches F1, the activity is still running until the user hits the finish button on the watch (the Stop Button).  All this time and distance is included in the general Connect activity (this is not the way it is displayed on MapRun Results where the pre-Start Punch is not shown but the post Finish punch is).  Basically Maprun pulls out the subset of the overall Garmin Activity.
I've attached a jpg of a short course I did situated near the end of my driveway but where I hit "go to start" at the top of the driveway well before the start location and then, after the F1 was punched, did not hit the Finish on the watch until I got back to the house.  You can see the Connect activity includes everything before the Start Location and After the Finish Location as time/distance.  If this is the cause it should be really easy to identify just looking at the Garmin Connect page or exporting this from the GC page and viewing it in any GPX viewer.
IMPORTANT - the "email track" from MapRun does NOT show the extra before the START (does for the after the finish) as I noted above - so don't use this to validate or investigate.

Obviously all this is just a guess without seeing the actual GPX from the watch.