Garmin coach not recognizing completed workout even though it shows up correctly as completed on my calendar?

Same problem here, my last 2 activities are not updating on the Training Coach section, they are however in my activities. I thought that changing something small in the workout (training days from 5 to 4 and back to 5) might make a difference, but actually it has just screwed up my whole plan. It's now showing a new plan and all activities for coming week are changed (tomorrows long run is now a short easy run).

Is anybody at Garmin looking into this and doing anything with these questions?

Exact same issue since beginning of the week ...
I tried the anser suggested, but it didn't worK.

If anyone has another answer please post it here!

Well I've been trying to get help from marine support in Europe (my watch is a Quatix 5). Don't seem to be able to get through to them that the watch is syncing fine with the phone and website as far as uploading activity is concerned, have even sent them pics showing the run in the widget on the watch, uploaded to connect and then nothing in Coach since last Sunday but all they do is send links to help on sync from watch to phone issues. So it was working Sunday and my Wed and Fri runs are both in connect but no updates to coach since Sun

Well Marine Support Europe tell me they have raised a case about this with the head office engineering teams in the USA, will report back if I hear anything.

I had the same problem and the solution proposed by 1368706 actually worked with a little modification. 

He said: I figured out a solution.  To briefly summarize:  a completed training workout shows up as an activity, but doesn't get recognized by the Garmin Coach.    Steps to solve (I'm using the Garmin app on an Android):  open the activity, click the three vertical dots in the upper right corner, edit activity, scroll down to Activity Settings, tap Event Type, change from Uncategorized to Training, tap Save.  Navigate to Garmin Coach and you should see your activity recognized as completed workout as part of your Training.  Hope this helps.

I already had the Event Type set as Training and it had not synced. I changed it instead to "Fitness" and it worked. I then changed it back to "Training" and it remained. I think just making the change in that filed prompts a resynch. It might be that any field might work but I can't tell as mins is now fixed. Thank you to 1368706

OK for the first time since last Sunday (a week ago) my run has appeared in Garmin Coach, still don't have the Wednesday and Friday runs in there but it is a start. The only thing different is yesterday my watch and phone stopped talking to each other and I ended up deleting the watch from the phone app and then pairing it with bluetooth and setting it like you would a new device.

I finally resolved it using RonHi method!
My two workout were already in "Training" and I changed them to Fitness, saved, and back to training and it synced with the Garmin Coach. My watch were off when I did that, I don't know if that changed somehing or not.

If you haven't done it yet try deleting the watch from the Connect app on your phone and reconnecting it as though it is a new watch. Maybe a coincidence but mine started working again after I did that.

I could identify the problem: on my garmin connect/garmin coach the workout has been updated due to  a reschedule action. that I did yesterday. Unfortunately, the updated workout has not been synced back to the watch, on the watch was still the old workout from before the reschedule. So I did complete the wrong (old) "Easy Run" instead of the adapted one (with slightly different requirements). Oh man...