Clarification: Bug, Coding Hindsight, or WAI?
Malzahar's passive is broken by Nocturne's ult, even if Malz is not the target of the ult itself. Given that all that happens is a temporary reduction of vision (not even an actual 'blind') and is not CC or Damage as the passive dictates it breaks under, I question whether this is intentional or merely something that slipped through the cracks, like Syndra being able to throw Baron.