As I was walking through Moorcroft Manor, I looked over my shoulder and noticed the Historical Preservation Motivator, Montague. What was he doing here? The Black Kats weren't around. Other NPCs related to events always packed up and left when the event ended. Why hadn't I noticed or cared before?
It seems kind of weird that the event NPCs for the Kataclysmic Confrontation stick around Moorcroft even when the event isn't on. My suggestion is pretty brief. Black Kats always have a naturally low chance of spawning in the Clockworks. During the event, their spawn rate increases and scenario rooms appear in Clockworks Tunnels and/or Candlestick Keep that have a 100% chance of spawning some Black Kats (presumably after or during a fight).
tl;dr The Kataclysmic Confrontation increases the Black Kat spawn chance and adds Black Kat scenario rooms to certain levels, while Black Kats always have a very low natural spawn chance.
To be honest I would prefer black kats to be in scenario rooms only outside of the event. This requires adventuring into the arcade rather than farming missions for a black kat.
Make the scenario rooms show up in candlestick keeps and compounds. Clockwork tunnels are overdone for that and compounds have branching paths so it works fine there.
But uh yeah, the reason those NPCs stick around lore-wise is because they're the caretakers of the little library there that gets assaulted by black kats every confrontation.