The answer says among other things:
This is a great book for you to understand when to use certain concepts, equations, and tables. This is a very good introductory text into thermodynamics for undergraduate students.
That's a bit peculiar as a recommendation for a book on differential equations. Sure some DE might be used in thermodynamics but still that description is not in line with the question.
The answer is somewhat subtle spam, there to place the link. Thus, the audit is not 'wrong', but it's one that is easy to miss.
The second is even more tricky in isolation. It does not look like a good answer, but yes one could let it pass.
Note that review-audits are not selected manually, but automatically, thus it's hard to avoid the occasional corner case.