I've had a few issues similar to this (Tacx Flux). ERG mode didn't work reliably. I went through Tacx (Garmin) customer service, Zwift Customer service, bought a CABLE to try and improve the connection... No conclusive answers, but Bluetooth stability seems to be the key. I had most problems when I connected my phone to a wireless speaker or headphones in the same room. Seems to be mostly stable now with wired audio.
Yeah I use wireless headphones too actually. The only issue I can see with that is that I need Bluetooth on the phone to use the companion app to pair with power meter & turbo...
I've had a few issues similar to this (Tacx Flux). ERG mode didn't work reliably. I went through Tacx (Garmin) customer service, Zwift Customer service, bought a CABLE to try and improve the connection... No conclusive answers, but Bluetooth stability seems to be the key. I had most problems when I connected my phone to a wireless speaker or headphones in the same room. Seems to be mostly stable now with wired audio.