Wattage Freeze

Im having issues with Zwift on my laptop, using tacx vortex and companion app. On a group workout my wattage will drop to zero. I unpair my smart trainer and put it back and no matter what I pedal it will stick to a wattage, for example 192watts, of occasionaly a nice round 2000watts. I will unpair again, turn my companion app on and off, bluetooth on and off and it still does the same thing. After a few attempts it will stop freezing, so I think it will be fixed then ERG mode wont turn on. Only way to sort it is to turn zwift off, and smart trainer off, then reset it all. Not ideal for being 50% into a group workout. Its happened two rides in a row now, close to cancelling my membership as its ridiculous. And before someone tells me its my internet, I previously had issues with that so upgraded my broadband to fibre and now workout in the kitchen next to the router!