Riven'E lockout bug

Was in a ARAM as Red side Riven. The game was losing and the Blue team was already at the door front laying siege on our Nexus. In a serial of action, Q and E, somehow the E didn't work out. There was no dash and no shield, and from the HUD ability bar, the E ability icon went dim. The E was never to be able to cast then. Possible replication method: During the actions of Q and E, I might have somehow pointed onto the minimap as result of trying to E toward right bottom corner. The bug happened to be revealed after the action. http://imgur.com/2zMZjio