If you finish a pvp duel completely, and then quit and switch characters for example, or just exit the game. If you return and try to pvp again the message appears "You recently fled a pvp duel and will have to wait 5 minutes".
Now, I completely understand it's not a big deal. I don't even mind that much. I just think it's a possible bug and could be fixed. Maybe not worth spending resources on, but I thought I would report it anyway.