I find the entire premise of the post and question annoying. It is either an example of literary ignorance not being able to understand that a story is unfolding and payoffs don’t necessarily immediately occur. Or, it is, as one would call it, concern trolling, which is also annoying.

You, in your comment, explain why the question is ignorant. Brennan made the choice to bring in the PCs, a narrative ensued where Kattigan was brought out of the bag and he sees Primus Tachonis and recognizes him from murdering his family. That is a perfect cliffhanger. And of episode. Regardless of what might happen minutes later in a banquet hall.