hi there! Found a solution on reddit whcih actually worked for me 
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All - I have been in contact with Garmin support and they've suggested a workaround that actually worked for me. Hopefully it helps others sync their calendars:
Below are steps that should allow you to load the Training Plan with the Calendar to your watch. It may look like a lot but it should only take a few minutes.
Connect your watch to the computer
Remove .fit files from the Garmin\Schedule, Garmin\Workouts directory and Garmin\Workouts\Schedule directory
Open Express > Select fenix 3 HR > Click Garmin Connect button to open your account in a web browser
These next steps are going to prompt Connect to sync your calendar to your watch because we are making a "change".
4) Move mouse cursor to black bar on left > Select Calendar
5) Click any workout in the Training Plan and select Edit Workout
6) On the Edit Workout page click the Pencil icon to the right of the workout name
7) Delete the last character/letter > Click green check mark to the right
8) Click the Pencil icon again > Add the character back > Click green check mark > Save Workout on far right
Connect should register this as a change to the calendar and push it to the sync queue to be sent to your watch the next time you sync. You can confirm this by clicking the Watch/Device icon in the upper right corner to see if a (1) appears in a blue circle. This means there is a pending item ready to be sent to your watch. Since we are already connected to the computer with Express just click the sync button in Express and it should push the files to the watch correctly.
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