Also keep in mind that MMR uses averages, so on top of ppl being able to have vastly different QM and SL MMRs (due to circumstances (mentioned above)), they still for ma team with a range of MMR, meaning @Op could be the end of the MMR, while the enemy could be the top of it.
Also worth mentioning, that Draft in itself is a skill, which influences SL MMR, but QM does it for you. Imo, this probably explains while on Hotslogs was it common to see ppl 1 League higher in QM than in Ranked.