I do think there is a tendency to over-index on one or two particularly straightforward tells, and for any given feature of LLM writing you can find places where people do also use that feature (they had to learn it from somewhere, and in a lot of cases it is good writing practice — for the context in which it is used). But I'm not talking about just that, but also the general tone issue: it's bad writing regardless because it's in most cases just not appropriate for the context it's been written in.

(TBH I think the biggest likelihood for false positives comes from heavy LLM users picking up their tics: it's a natural tendency and I've already seen a few cases where it seems like that has happened).