Forced to reconnect to a custom game

So I decided to try Jhin out in a custom game. I started it up, everything was going well just trying out his kit, and then I had a massive lag spike and the client crashed. I'm just like ok no big deal I was pretty done with that custom anyways. I restart it and then I don't have the option to quit. To be clear, this was a game with me against 4 bots, there were no other players in it. The game ended eventually, but you're supposed to be allowed to leave custom games.