I’ve never done a Garmin edit, but I do see this:
Note
- Please read How to edit a run from Garmin if you want to update this activity based on changes you have made in Garmin
It shows up at the bottom of each activity.
Hope this helps.
Eric
PS. There’s an embedded link in that text. It’s kinda hard to see, at least for me, so here it is: How to edit a run from Garmin