So it would seem that every time you go to delete a message from your mail box, you will always get a message that wants to make sure that you do indeed want to delete the mail you got. My guess is that the game isn't recognizing that you've already gotten this queue and is always playing it which is very annoying.
Also as an aside the hotkeys for dialogue options aren't functioning at all. I went to click the default hotkey for this ('e') and wasn't able to progress with the conversation without manually clicking on the option. Not as ground breaking and annoying but a small bug nonetheless.
Member of Victorem, RÁGE ; Decibel Alumni (RIP)
Kalista Schefer: VR16 AD Sorcerer; Alliance Rank 22
Noxus-Katarina: VR16 AD NB; Alliance Rank 30
Grxknight: VR16 AD DK; Alliance Rank 16
Lorelie Aedel: VR16 AD Templar; Alliance Rank 8