Small Thing Wrong with Matchmaking Queues...
In the queue you get your primary role and your secondary role. I've tinkered around and noticed that the system doesn't differentiate between them both. What I mean is that the system in place right now doesn't distinguish between the primary and secondary role and puts you in whatever role is first available. It makes sense it would be that way for convenience of finding a match, but the problem is that the primary role should in theory take precedence over the secondary role. When I've went into queues I've noticed that right as I go into queue, not even a second in, I get a match for my secondary role. I've actually noticed that this happened a couple times.
My suggestion for change is to make it so that there is a 30-45 second wait to see if there are any spots for your primary role, and then after, search for secondary role positions.