Leaverbuster penalty in Invited Game

I joined a game for which I had been sent an invite and within the space of 30 seconds, had two leaverbuster messages and lost a heap of LP. It seems I may not have completely joined the game. Before quitting, I saw a message from one of the others saying I "didn't have a queue", so even they could see something was wrong.

This was about 13:25 AEST on 101/10/2015