whats up with the auto attack missle disappearing?

when i die and i know im going to get a kill becuase i sent my auto attack but they flash and i see the auto attack just disappear! whats up with that?! happened with corki and jinx's rockets.

also, i was playing a friendly bots game with a friend as ezreal and i qed wukongs clone afterit disappeared. it was just after it disappeared but the q still registered as if it was there.