Ranked Queues are working as intended?

My Mid is ranked silver 1 and I am getting matched against silver 1s - gold 4s. Great, that makes sense to me. My other roles are still in the Bronze tier, yet I am getting matched against the same people, silver 1 - gold 4 on other roles.

If the separate ranked tiers for roles are going to mean something, I should have a separate hidden MMR for each tier, not the same MMR for all tiers but different leagues.