Can't Change Runes in Pregame Lobby

It doesn't happen every time but every once in a while I am completely unable to open my rune pages in the pregame lobby, and it really puts me in a difficult situation if I haven't picked one of the previous few champions I have played and have rune pages for. I have had to dodge two games now because of this, but I have had the bug four times since the start of 9.14.