I'm about to leave the Garmin ecosystem over this.
I track my weekly activity output by Intensity minutes - I don't care about steps or calories or anything else - I want to know how many minutes I am spending in various Heart Rate Zones. Fitbit did a fabulous job with this with their "Zone Minutes" metric (but Fitbit doesn't care about athletes).
Garmin's Intensity Minutes was working fine for me until about 3 weeks ago. Since I've been forced indoors by the weather, my Intensity Minutes isn't counting my bike trainer rides which are being tracked with an Edge 830 with a heart rate chest strap.
If there isn't a fix for this I'm going to try and go to some other platform.