He does miss some of the details Ragashingo noticed. Notably, Dregdon destroys the town he once saved as Rezyl.

I have a theory that the darkness within Yor fed on the destruction of hope. That is why it was so much more painful when he destroys Palomon, and I think that is what he was attempting to do when he allowed The Last Word to be left with Shin. This attempt to grow and then snuff out hope led to his own destruction. Byf suggests this moment was a hint of Rezyl showing through, but I think it was a calculated act of the darkness. This wasn't Anakin telling his son that Luke had already saved him; this was evil getting consumed by its own machinations.