[Gameplay] Flex Queue matchmaking quirks?

So matchmaking went back to the old "Riot quality" meme days, and decided to do this. Haven't had a such good laugh in pain since season 2. Ahh nostalgia.

The story part: I decided to duo with my GF, me on Gold 3 (100LP) and her on Silver 5 (0 LP). Had numerous games with only minor rank differences, perhaps 1-2 odd people sticking out, but by match histories, it could be due to win/lose streaks. Picture speaks for itself, after looking through match histories, we were the only premades in this game, and no-one had a huge win/lose streak to have this huge damp on his rating. I know these sites can have inaccurate data (mostly the presumed MMR), that's why I also looked up their rankings in-client, which shown the data to be correct (unless...).

I refuse to believe there should've been this huge gap in differences. The servers were populated enough, matching happened consistently quickly, and never saw the same players twice, which to me indicates this wasn't due to lack of players.

If some players were switched around it could've been balanced too, and I see no reason why it couldn't have happened. (again, no other premades)

Not mad at all surprisingly, from the first second I knew this was lost LP, so might aswell just play it out until I can, and hell it felt good to trounce the Dia-Plat botlane into the ground because they got cocky. Learnt a trick or two aswell. Just... weird.

TL;DR -> Not sure if bug, but perhaps worth looking into whether something is up, or I just got caught in the 1%. Matchmaking shenanigans with no logical reasoning behind it. Haven't experienced such an offset game in years.