I had the same issue last week and solved it by uninstalling and reinstalling the Garmin Golf App.
I can't be doing that after every round!
I have again two almost duplicate rounds showing on my app, the first one if I enter it has the holes listed underneath as I'd expect and I can edit the shots.
The second shown in the app, when I click on that I can a message saying "Garmin Golf - Something went wrong. Cancel or Retry"
Retry just refreshes the same message.
Cancel clears the message and I'm left with a blank scorecard.
Clicking the 3 dots top right allows me to choose "Delete Scorecard" - but then nothing happens - it just returns me to the list of scorecards and it's still there.
Please advise how to delete it and also why this is occurring?