Got Promoted, but got Demoted below a rank when it said I got promoted.

Hello! I'm Gloribth, and I have encountered a rather infuriating bug while playing Ranked games.

As you see, I was in a series and I got one defeat and a win. I won another game but guess what happened? I got "demoted" below my rank (I was Silver Four.) to Silver Three, when I should've been at Silver Five. And I looked into the "League" tab to confirm if I did, in fact, got "demoted" when I should've been promoted to Silver 5. I saw myself in Silver 3 again, from Silver 4. This is rather unfortunate, as I went through sweat, tears, and anxiety to finally think I have triumphed into Silver 5. It didn't happen. Now I'm "promoted" to Silver 3 from Silver 4.

A lot earlier, the opposite happened to me. I was in Silver 3 and I lost a lot of games, then I managed to get "demoted" into Silver 4. I feel like this is the only thing that's happening to me.

Can you please look into this bug, Riot? It'd be much appreciated. Thanks!

EDIT: Also to note, that it says that due to my "inactivity", my ranked thingimajig will "decay" even though you guys (Riot) disabled decaying in Bronze and Silver leagues (Also Gold, I think?). This message only occurs if I get "demoted" to a rank above what I was currently in.

EDIT 2: This is on the NA server, not PBE.

TL;DR : Promotion gave me a demotion, demotion gave me a promotion.