Quinn's Ult is immediately stopped by SLOWS, despite the tooltip stating only damage.

Jhin's mine thing, Iceborn's slow field etc all cause the ult to disappear, I'm pretty sure this wasn't the case on release of the rework and it is not written in the tooltip so there seems to be no reason for it to be happening.

On release, I believe stuns and immobilizes stopped the ult, but not slows.