Hextech S rank bug [Client]

Me and my friend played a normal draft game, he played Twitch and I Karthus . When the game was over we both received an S rank and both got one box. I had already earned one box this month. The client thinks I received two boxes for the two S ranks and took away one of my four boxes I can receive this month. Now it says I have earned three boxes for the month when I only earned two. I do not know if my friend has the same issue. Please fix this bug, thank you.