Cult of the Cursed Blade and Kabal of the Black Heart

So the Cult of Strife has long been referenced as having an iron clad working relationship with the Black Heart Kabal and essentially being under Vect's patronage. Was really surprised to read in the new codex how many times they referenced the Cursed Blade conducting some joint activity with the BH and even being the location to host Vec't wake. You would think that would have all been Cult of Strife. I wonder if its the case of a the writers just trying to branch into a wider list of "chapters" or is there some meta plot there that we will see evolve over the course of this edition.

Strife and Black Heart had a bit of a religious falling out over the topic of Ynnead.

Lelith sent some of her forces to aid in Yvraine’s quest, sort of as a means to put a toe in the door of salvation in case it came to fruition. And at the same time, Vect is on a headhunt for Yvraine as punishment for breaking the ‘no psyking’ Rule and causing a massively expensive disjunction.