Sion health gain passive

I've found that sion's w passive doesn't give the 10 bonus health that it claims to for killing large creatures. Wasn't sure if this is intentional or just a bug, but it is a bit misleading. I haven't found out if this also happens against enemy champions, but i thought i would point it out.

Edit: I believe this has been fixed, because in my last few games as sion after posting this he did gain the bonus 10 hp. Don't know if this was a bug or what, but hopefully doesn't return.