I usually play in mid diamond. I was on D3 (NOT PLACEMENTS), had 4 wins and 2 loses as tank (no leaver penalization either), and then I won the 5th game and got “ranked up???” from Plat 4 to Plat 1???
What the actual f is happenning with ranked games?
I never received my ranked rewards for Diamond and now this.
Lets be honest, no one in Blizzard reads this forum. This is more to vent my anger than to “report a bug”.
You are not alone in experiencing this bug. Assuming your win-loss ratio is positive, you might be experiencing the bug in which during a rerank, your initial rank is demoted five subdivisions before the adjustment takes place. There’s a ton of posts under my thread under: Incorrect Rank Adjustment regarding players with those exact bugs if you’d like to read more about it. Comprehensive Thread Of All Top 500/Competitive Bugs. If you can, could you record your bugged rank adjustment, making sure that at some point in the video it shows your pre-adjustment rank, either from the queue menu or the career profile, and link that video to the thread? Any help in spreading the word about this megathread would be greatly appreciated.
Unfortunately, I don’t have this recorded 
That’s unfortunate. This bug appears to be account persistent however, so if you could, it should be fairly feasible to recreate. It would be a hassle to do, but more evidence of this bug would certainly be helpful to the Devs.