Malz new passive bug

While testing out the new Malzahar I was playing around seeing how the new passive affected game play, and discovered something a bit odd. The enemy jungler was a Nocturn, and every single time Noc triggered his ult while Malzahar's new passive was up it went on cd immediately, regardless of if nocturn dashed to Malzahar. As far as I'm aware Nocturn's ult upon triggering doesn't set off a global CC that would affect this, nor does it deal damage. Both of these are the only given ways for his new Passive to go on cooldown.

If I am mistaken about Nocturn's ult, or Malzahar's new passive, please feel free to correct me and let me know so I can know for future reference.