Put fill as primary then, you'll get supp less times
The problem with roles in the queue is that depend on the availability of players in a certain moment. It happened at times that you got 2 or 3 sup mains, and other times you got 0, the fact is that the first circumstance was more common and so people went with pick order to settle the matter
In the new queue, this thing translate to the fact that often when you fill you won't have the guys that will play support in your game so it place you as support, but the other times when there are people queueing for sup you would get another role