Darius E bug or not?

Ok Riot, Today I learned something sad. I don't know if its a bug or not but i got into a game playing Darius my fav champ. 5 minutes in I'm 0/2 because i cant auto attack minions!?!? I try to find out why. I realize every time my e hits an enemy champions i can't auto attack using my cursor/right-click. I am able to continue auto attack with my cursor once i left click on the champion which is annoying in team fights! please tell me if its a bug or not, if so please fix it