There should be a way to edit data on Garmin's Connect. This should include weight data, other health data, activities, etc. There are times when something goes wrong with communications. Being able to edit the information is essential.
You can edit the data. At least the data for your activity. Distance, times, Calories, elevations, HR bpm, power, etc. Just click the pencil icon while on the individual activity and select full edit. If you are already on the new version of GC, I can't speak for that.
