Deranking and staying the at same rank after winning

I’ve deranked once now after winning my 7 games and stayed at the exact same rank twice. I was plat 3, won my 7 games and went down to plat 4. Then I proceeded to win my 7 games again and stayed at plat 4. I did manage to rank up to plat 3 in between. But today again I won my 7 games and stayed at plat 3. I would be diamond now if not for these bugs.

How many games were losses/ties?

I had maybe like 3 losses, max amount of losses/ties was 5. But when I deranked I had like 3 or 4 losses.