My recently failed review audit got me to wondering which review audit types allow commenting and which don't allow them but advise you of this.
If you do a volume of reviews, you've probably seen cases where the attempt to post a Comment results in a red box popping up to inform you that "this is a review audit".
The case linked above is a case of First Posts. The actual post is not a first post by any means, but the notation used in taking a "limit without l'Hopital" was quite laconic. Assuming a true first post I wrote a Comment encouraging the user to (a) incorporate limit notation and (b) give a justification for the steps where a limit is taken.
It seems to me that Comments (of a constructive kind) have a non-pejorative sense on First Posts (compared to downvoting or flagging).
I wonder if the revisions to disabling commenting on review audits have been applied selectively by design, or if perhaps this is logical branch that got overlooked in making the changes.
Update: I surmise from this additional datapoint that review audits for Late Answers also allow Comments to be posted, apparently with the logic that commenting on a "bad" (i.e. previously removed) post gets a passing "grade".