Can anyone explain this matchmaking pattern?

Hey all. So recently I've run into a pattern in ranked matchmaking that is honestly frustrating me. I am currently as of this post Legend 5 at 3760 MMR.

The pattern basically goes like this. When I first got to around 3400 MMR my friend and I suddenly started winning almost every match. This happened until I got to 3800 MMR. I was two wins away from getting Ancient 1. Suddenly we go on a uncontrollable lose streak to the point where we lost 300 MMR. It gets to the point where I derank from Legend 5 to Legend 4. Now at first obviously I was upset but I didn't think anything of it.

That is until it happened again….

After I deranked suddenly I started to win a bunch again. Again to the point where my friend and I had almost a 80% winrate. I'm approaching Ancient again. I'm super excited. Then just like clock work I get within exactly 2 wins of reaching Ancient and we go on another losing streak. Again to the point where we lose around 300 MMR.

I derank again back to Legend 4.

I began a joke I said "OP Friend were gonna win a bunch get within 2 wins of ancient and then go on a lose streak"

Except it wasent a joke.

For a third time we go on a massive wining streak. We go from 3500 MMR back to 3800 MMR. Then? We have started on our third Losing streak. Again starting at exactly 2 wins from Ancient.

I find it very hard to believe that this is coincidence. I have solid proof that this is a ongoing pattern. Does anyone at all know whats going on? Has anyone else experienced this?

Here is the time line in pictures Starting from more recent to old.

This whole process has happened over the course of 6 months.

This is the the beginning of Loss Streak 3 before that first CM game I was 2 wins away from Ancient 1.

This is the entirety of the climb from 3500 to 3800 MMR. Calling it Win rendition 2.

Here shows the the end of Loss rendition 2. Once again loss's stopped at around 3500 MMR as soon as I dreranked to Legend 4.

This is fast forwarded slightly and shows the Beginning of Loss streak 2. Once again at exactly 2 wins before reaching Ancient 1. This is the beginning of Loss rendition 2.

This continues to show winstreak 2.

Still showing winstreak. I understand I'm not showing all data here. Otherwise it would be 2 full pages of games.

Here we have the end of loss streak 1. Again winstreak begins immediately after I derank.

This a shortened continued loss streak 1.

This is the beginning of the very first Loss Streak. Again 2 wins away from Ancient 1.

I would love to hear all of your comments and any ideas as to why this happens. I can't figure it out.