Hi @Steve_Venkman! Hopefully it won’t happen again, but you might want to check out this link: https://forums.zwift.com/t/garmin-hrm-no-signal-solved/209400/108
I started having the problem after the previous update and haven’t been able to solve it yet (Garmin Dual, which I pair via bluetooth and the companion app to AppleTV). My first ride after the update, the HRM showed 75 bpm the whole ride, but with all subsequent rides it has appeared to be connected, but I get the “no signal” message and 0 bpm. I hope the new battery does it for you!