Hello,
I have the same situation and it is the second time that it happens. The first time was solved by doing a hard reset, but is not a solution due to the fact that it was a couple of weeks ago. This starts to happen after 12.10 update to 935. At the moment I am not able to send any kind of workouts created in Garmin connect, added to the calendar or from TrainingPeaks, basically I can't do any guided workout, very frustrating. Hard reset is a major trouble and to much time consuming to be performed twice a month. NOT ACCEPTABLE.
Best regards,
A. Duarte