I just got a Diamondback 1260sc, and I can pair it without issue with Zwift on my iPhone and the data that comes from the bike trainer to my phone looks great, as I pedel faster/harder the watts go up in Zwift, if I sustain a power level it shows that wattage level. When I do the same on my Garmin fenix 6 the watt levels are incorrect by a lot. If I sustain a power level it shows zero watts, if I go down in watts it shows zero watts, if I go up in power level it looks to show an increase. The result of a 25 mile ride with my Garmin watch was a 2 ~ 3 watt average for the ride, which if I had to estimate should have been closer to 140 watt average. The cadence and distance seem to work flawlessly with the Garmin.
I have tried removing the device from Garmin many times and have had no success in any behavior changes. I even tried adding it differently, once through the sensor/accessory menu and once straight from indoor biking, and both resulted in identical behavior from the integration.
Was wondering if anyone else has seen this behavior and maybe has any ideas to help.