Why does Akali's w not cancel her auto attacks like all other stealth?

With most stealth abilities when you go invis it disables your auto attacks so you don't cancel it accidently. the same applies to attacking outside of unguarded brushes. My question is why doesn't this happen with akali? I've had more times than i can count where I engage and go into stealth just to immediately auto attack something and lose stealth. Even when mashing S it still is difficult to not auto attack