I'm glad this is being talked about. I noticed it too. I find Opus 5 to be overly (and unhelpfully) critical, in a sort of well-actually way. It ignores nuance in my direction or prompts.

It is better at engineering tasks; I've seen an appreciable difference in its problem-solving abilities. But perhaps that same thing makes it kind of an annoying prick to work with on anything non-engineering, for which I stick to 4.8, where the prose is a little more florid rather than pugnacious.