I started to use trainings implemented by Garmin and my guess is that sync between 1040 and garmin connect is completely random. Main training plan was more or less correct, but any trainings I added to garmin connect site didn't appear in 1040, unless I did some magic. I read that it syncs after you restart your Garmin unit. It worked as a bypass several times, but now 1040 shows me completely different trainng plan and no trainings that I added by myself. Garmin connect site and phone app show it fine. I restarted garmin unit twice, but the magic no longer works.
I can see some posts from years ago with the same problem. It's useless - you cannot find on a unit training you planned.