When I selected coffee break, the trainer became disconnected and I had to restart zwift to get back in. At least one other zwifter had the same issue
It would more useful if you also stated the make and model of trainer. Its not at all beyond belief that some trainers will do things that lead to a timeout disconnect.
Did it happen more than once? My wife’s trainer right next to mine once disconnected twice in a row right when I used my own companion app screenshot button. She yelled at me