Getting my secondary role way more than primary role????

My secondary role is mid btw (and main role is adc).

In the past 10 games, 6 of those have been mid, and 4 of those have been adc. I got my role more with the old system (pick order).

I honestly don't understand how this new system is supposed to work, but I thought primary role was supposed to have priority over secondary? This doesn't seem like it's the case.