Editing Garmin Coach Training Fails

Hi,
I am trying to edit one of the training from  Garmin Coach Traing Plan.

Training is now visible in the training library on the watch.

Edition is triggered from the watch, but it is done in the Connect AP.

When trying to save it, I get error message. Sth like "Changes were not applied. Try again later".

I opened a case with Garmin Support, but it is really bad and really not willing to resolve the problem Disappointed

Any one had a silmilar issue?

Cheers,

Lukas