Queue time disparity? ADC/Mid vs Mid/ADC

I just did something that seemed very odd to me. I wanted to play Jhin, not really caring if I played him Mid or ADC. I started queuing as ADC/Mid (Normal Draft), and had my longest queue time yet, over 5 minutes before I stopped it. I swapped it to my normal order of Mid/ADC and got a queue in about a minute, still putting me on ADC.

So there was an opening for an ADC, but queuing as ADC didn't give it to me as fast as queuing for Mid did.

Someone left that lobby, and I get thrown into the waiting again, with again about a minute before finding another game (a few AFK checks didn't get passed, but I saw several AFK checks). This time, I get Mid.

Have any of you found your Primary/Secondary to be faster queuing than your Secondary/Primary, or vice versa?