The same thing happened to me when I hit "transmit" on my state taxes. The only choice was accept it or cancel, so I canceled. I can't remember if that closed the Turbo Tax app, or put me back at the beginning, but next thing I remember is having to leaf through the pages again to arrive at State transmission again, and then it went through normally. It was disturbing to happen at such a crucial stage. I thought it was a scam trying to divert my tax return. This was on 2019 Premier for Mac/ PC.
