Kayle E goes through Yas W

Kayle's E-enchanced autoattacks don't have a projectile.

Therefore, Windwall doesn't block them.

IIRC, this works the same way for autoattacks from:

Her e isn't a projectile. That's like trying to wind wall a Cass q. It's a splash on target effect, nothing actually gets thrown at you like Kayle's q.

That is not a projectile. Or do you see any kind of bolt flying from kayle to yasuo? It is a melee attack with increased range, but still a melee attack. Melee attack can't be blocked, so it's not a bug.