[CLIENT] Club Chat Reoccuring Notifications

Hi there! For some reason, every time that I log on to League, it gives me a notification of a chat message that someone sent back on June 20th. No matter how many times I read it, it still pops up every time I log on as though it's a new message. I have even since MUTED the club chat in order to try to get it to stop (because it bugs me) and it still pops up.

I noticed people in EUW were having this problem, but didn't see a discussion about it here, so I figured I would post my own.