I'm not finding anything on this specific issue:
I did a triathlon using a 910XT using Auto Multisport. The workout is on the device (i.e. it says total distance is ~140.6 miles). The Swim, T1, Bike, and T2 uploads fine to Garmin Connect (as far as I can tell) HOWEVER, the run portion is not uploading at all.
When I look in the Activities folder, there is just one big file (as opposed to 5 files for each section), but I think I've seen that before. And, this file really doesn't work importing to Training Peaks and/or Strava, but again, I think I've had that problem before and so always skip it.
I forced my device to upload data again, and same problem. I'm doing another force (just in case).
Any other ideas?