What is up with normal que with 3 people

Me and 2 friends qued on normals and i was host and when we went into champ select it put me in the pre game lobby, then i left and got 6 minute ban, and then one of my friends hosted it and we did it again and it did the same thing to him, but he waited until the end of the champ select timer and it 6 minute banned him, pls fix this? thanks if you do..