So I have noticed a bug when using the companion app to conect devices.
I was using the companion app due to the Zwift Play Controller causing zwift to crash on PC. The companion app connection is pretty solid due to being so close to the devices and away from wifi.
BUT, if you teleport or change world (for instance, by going through the climb portals) then all of the connections drop out. No bike, no ZPC, no HR.
Nothing, that is until you go into pairing - then they are all shown connected… until you go back to the game world at which time they cut out again. Only way to solve is a reset of zwift.