After spectating a game you cannot select a champion in champion select

I have had to wait for a dodge timer twice now because I have joined a friend in lobby after spectating their game.

Exact process both times:

1. Spectate a player to wait until they have finished.
2. Exit the spectator mode by going menu -> exit
3. Join the same player in lobby because they invited you.
4. Accept match.
5. Champion select starts with a button saying "Quite Spectating" which appears where your summoner icons would usually be.
6. All champions disappear, timer instantly goes to 0, and can no longer see anyone in lobby. CAN chat to them, can't see responses. They can see what I've typed though.
7. Timer goes to 0 and I get penalised for queue dodging.

I'm not sure what I could remove from the list above and still reproduce the error, but I don't want to test further and dodge more games...