In the past few weeks this annoying bug is happening often. You queue up for a ranked game solo/duo, the pop-up window shows up and you press the "Accept" button. The sound of the "accept" button can be heard. You enter the champion select menu and the "Match found" pop-up window is still there, not disappearing! At this point it is a "dodge" 100% and you lose LP or the chance to win your third promotion game. You can't press anything else in the client. You can't select a champion to play or ban and can't click on the top right buttons, nothing. The sound of the pop-up window is still there and the thin light blue circle is still flowing. Even when you press accept or decline buttons multiple times the sound will always be produced but it will not remove the window. That is pretty much all you can really do.
Hope this one picture is enough for you. As you can see, the window is still in the lobby, not disappearing. You have to close the client with task manager or alt+F4 since the top right buttons, ( ? _ o X), can not be pressed.
I reinstalled the game, but it continued to happen. Any other advice how to solve this ? I even enabled the "Enable Low Spec Mode" but it was not successful.
Thank you for you time reading this and I hope that there is a way to solve this !
Imgur link: https://imgur.com/a/6JjKkAZ