Cass was finally if not editorially mandated to be accepted into the circle, wasn't, and is seemingly ignored as Bruce goes off and does his RIP and Final Crisis disappearing shpiel. (which is a shame since her and Damian interacting would be incredibly interesting to see) For her to be sullen, and confused, is perhaps quite new for her like this,
I can definitely get behind Cass feeling confused over the death of Bruce, and realizing that maybe she had replaced her father with him rather than just found a mission (if they ever establish that in detail). But the reason people ignore the mini is that it's OOC and poorly done all over the place. And in many ways it frankly seems like the writers have ignored it. They've put a surprising amount of care, imo, in figuring out the emotional landscape of the Wayne family in the wake of Bruce's death. Cass was a part of the professional aspect, but not the family drama.
This is good for all the characters, and I've seen Spoilerasmanbatgirl possibly coming ever since the very peculiar line in Robin about him not wanting to see her in the Spoiler costume anymore.
I have never heard anything peculiar in that line. That she's now Batgirl means she can now sort of jokingly say that he got his wish, but there was nothing in the original context that was anything but straightforward when I read it. I think I even asked Fabian Nicieza about it because I was confused by people saying it meant she was going to be Robin, and I think he confirmed that there was no hidden meaning in the line. He probably had no idea Stephanie was going to be Batgirl when he wrote it.