[Gameplay] Katarina's Passive and CC

I noticed something playing Malzahar against a Katarina. She had jumped in and threw a dagger up (as new Kat is wont to do), but I hit her with Nether Grasp before it landed. While she was suppressed, her passive still picked up her dagger and did a chunk of damage to me (again, she had Shunpo'd in, so she was close) allowing her team to come kill me before she died.

Is this working as intended? Should she be able to pick up daggers and spin for damage while controlled? I hate to say it doesn't seem realistic in a game where an ice bird can fight a toxic rat, but it seems a bit strong.