Is this intentional or a bug? Although the 
didn't spellshield the 1st Zac Q (the skillshot), she was still dragged/displaced by the 2nd. She still said "Nice Try" and got the mana restore but it didn't prevent the CC.
One, if she hits the shield after the skillshot connects, then it shouldn't block. I suspect what happened with the mana and audio cue was that zac or someone else attempted another ability after the pull in.
Apparently, Zac's second Q counts as an auto attack for all purposes except for the fact that it does not do his physical damage. It can be blocked by Jax counterstrike, pantheon passive, shen's blocking ability, and Teemos blind. I thought that was a bug, but Riot never responded when I pointed that out, so I imagine this must be intended as well. Makes no damn sense, but whatever, Zac's rework makes no sense at all so this is just par for the course.
Because you got hit by the 1st Q pre-spell shield, that doesn't make you immune to the CC from the 2nd Q because the 2nd Q doesn't hit you to trigger the pull effect. It's not like Morgana's Spell Shield that makes you CC immune which is why you can still be slowed in AOE zones if you walk into them.
Same thing happened to me
