This just reminds me of early days of rainbow6:siege ranked, when they did the same mistake.
I got placed into silver because of it, even playing on platinum level.... my friends got into platinum even i was the carry, but they didn't fool around so much in casual like me.
During that period until they fixed it, i got so many kills and wins in ranked, that my stats are still better than from proplayers and takes forever to even out. People still keep asking me if i cheat or how i got so good stats and i have to explain it every single time.
I realy would like to know how their ranking works, i got a feeling that it doesn't promote the best players if i check the points after a match (sometimes i got most kills, assist, plants, defuses and less death... and yet i'm not on rank 1 from efficiency and points, but MVP). Maybe they just used a moba algorythm...