I finished the Cultist quest in the Krasno Catacombs, however the npc only has the option "Nothing to report yet." The quest log says "Cultists left the caves so fast my head spun. Now I can tell about it to my employer in the smugglers den"

Doing the "Tattoo" quest from the same npc fixed the problem, it made the options available to complete both of those quests.

Hello!
Yes, there seems to be a bug that you can't report the quest at some points of the conversation.
Sorry for the inconvenience! We will try to fix it ASAP.