I was not under that impression. I am just wondering why Kubo has Ichigo in his Shinigami form here, when he did not bother to put it in the final chapter?
Because apparently, there was no need for Ichigo be in his Shinigami form. Bear in mind, though, that a volume doesn't consist of just one chapter, plus it's a story of a shinigami - yes, Ichigo is a human but for the most part, he's seen as a Shinigami. And it ties in with the first volume where we have Ichigo as a Shinigami.
... He's turned into Isshin
Exactly my thoughts when I saw the cover.