This has happened to me twice now. Most of the time my client is fine, but I do have occasional lags.
The last lobby for example. Someone was banning, but the timer got down to 0 and stayed at 0 for like 2 mins. Then I saw someone in the chat write "pick" and I was still sitting waiting for the bans to appear. I was then thrown out of the lobby and in the chat box it said I was thrown out for not locking in my champion, even though the option for me to lock in my champ didn't appear.
This has happened to me before where someone's timer was sat at 0 for what felt like forever, only all at once everyone's bans appeared then it was my turn to pick and I could lock in. It then lagged again later on as another timer got to 0, but the lobby was still on screen, then everyone locked in at the same time and we went into the game.
This is the first time it has stopped me from locking in my champ though, but I feel like it is going to happen again.
Anyone else having this issue?