Hello,
Using TNet 3.0. Latest Asset Store release.
I open a server in code using:
TNServerInstance.Start(25565, 25565, "ServerData.dat", true);
TNManager.Connect();
TNManager.JoinChannel(0, "Lobby", false, 5, null, false);
I join the game as normal, it creates a server gameobject with a TNServerInstance script as normal:

Then I disconnect using as well as calling TNManager.Disconnect:
It boots me back to the main menu, as normal. However, I press Host server again and:

Clients are unable to join the server. Have to stop and start play testing in unity to set it back to normal.
Am I doing something wrong here, or is this just bugged?