Winning Series and it demotes me back to my previous rank

https://prnt.sc/i9n2kz <-- Me winning my last game to promote to Gold 2 https://prnt.sc/i9n35f Na.op.gg Match history before I won my last game https://prnt.sc/i9n3cj Winning last fizz game @ 9:39 PM PST, and losing LP for a win? https://prnt.sc/i9n3st Match history, Proof, So I won a game to go into my series and since I lost my last series I get a free win for this series, So I got in Series with 11/8/8 Game, and lost one game and won my latest game, which it should've promoted me to gold II, but instead it counted my last win as a lost and made me lose my series and now im back at 67 LP???