Zed Ulti Bug

I was playing Zed a few days ago, and was playing against a Katarina in mid lane of Summoner's Rift. Anyhow, I popped my ulti and mid attack, was killed. However, my shadow did not disappear, and instead provided vision to mid lane on the map. When I pressed my Q and aimed my blade nearby the lingering shadow, an arrow would come from it, as it normally would if I had a shadow out. However, upon activation did not throw a blade. The shadow stayed in the lane for the rest of the game. Sorry, but I don't have a screenshot.