Unable to remake a game.

I was in a game on December 15th at approx. noon PST and our mid laner never connected to the game. There was never a notification that the player had connected or disconnected but the player never left the fountain, never bought items, and never said anything in chat. When the 3 minute mark came and we were ready to remake we got a message saying that no one was disconnected and that we were unable to remake the game. At the end of the game the person did not even get marked as AFK with their name highlighted in red.

I thought that if a player never left fountain or never made contact with an enemy, they would be marked AFK and booted from the game. Can you please explain how this happened? Linked is the match in question.

Thank you