Garmin indoor rowing fails miserably on so many points...
1) Doesn't work with low stroke count, so the strokes recorded are 2 (if you're lucky).
2) No way of editing this poorly recorded data as the activity still shows fields for cadence.
3) ErgIQ - the working app for this can't use Garmin fields and ConnectIQ fields are ignored by Connect.
Ergo the Garmin watches are not worth using for indoor rowing...so why bother having the option for indoor rowing if it's worthless.
Either fix it or delete it...