Soraka/Sivir bug!!

That's an interesting discussion point actually. Is it really a bug?

The spell is blocked by sivir, and so the damage/slow is not applied. However, Soraka's W states that for each champion hit, she is healed. Sivir is still hit by her Q, it just doesn't apply any of its effects. One could argue that the Q spell was indeed blocked by sivir's spellshield, but the passive W effect is also still applied - because the condition was met.

I can see an argument for both sides, personally I'd assume that whatever happens in-game now is intended unless otherwise stated.