This is a broken procedure, and is not what they do. It would make ranking up harder than necessary, which would make match quality lower for everybody. What is done is described in How Competitive Skill Rating Works - Season 17 → Summary → Summarize matchmaking, rating, and progression for me. Note the references as well. That post is out of date because it doesn’t include role queue, but the basic ideas haven’t changed.
How Competitive Skill Rating Works - Season 17 has 65 references. Perhaps, though, you should start with http://www.moserware.com/2010/03/computing-your-skill.html. It’s about Microsoft’s TrueSkill rather than Blizzard’s matchmaker, but they aren’t really that different and that post does a good job of explaining the philosophy and math behind these kinds of systems.
You seem to believe that it is up to me to prove to you how things work, and unless I can do that, your beliefs are equally valid. That isn’t how knowledge works. You have to understand it for yourself. I can’t make you understand anything.
And we can’t both be right. Reality doesn’t care about validating your opinions.
You’re not really giving any context here, but the system is unstable because of the introduction of role queue. You need to play ~150 games for your new rating to believable. But if you maintain the higher rating after ~150 games then either you’ve gotten better as a player, or your skills are more suited to the new role-queue meta. There is nothing strange about either of these possibilities.