The tell here is the "One ..., then ... <negative>". This is "not X, it's Y" with the clauses reordered.
For some reason the current crop of LLMs are really insistent on generating contrast between two things in every statement.
>The tell here
Is this AI written? It has "this is the smoking gun" vibes, just rewritten.
The problem is that the "it's not X it's Y" construction is very useful, and shows up a lot in human-written text.