That's another issue of the current system, where it decides to reroll your assigned role if you're put back on queue after somebody dodges or forgets to lock in their pick/ban.
Earlier today I dodged a normal draft after I saw someone pick Soraka for mid, and after the wait time I got into a game with a top Ashe running heal/ghost but didn't want to risk an even longer dodge time so I decided to give it a try. Mid was winning and we at bottom lane were doing OK, but that Ashe fed like there was no tomorrow and the enemy team began catching up. The best part was that there was not a single tank in our team, and everybody kept overturning my surrender votes for some reason despite us being unable to secure any objectives while our foes were taking our turrets down and killing dragons and barons with total impunity. They even had two very powerful late-game threats in Vayne and Veigar (who had lost mid but got enough kills afterwards to buy good items), but jg Master Yi was still saying "we can do this, guys" every time I started a surrender vote.
