Only reviews for stays that occur and are completed during the evaluation period, which ended on September 30th, are considered for that quarter's Superhost calculation. If your guest wrote a review that was submitted after October 14th, then their check out date must have been after October 1st.
I am not going to argue about flaws or pressure. I think almost everyone agrees that both of these attributes are words that fit the current review system. However, the rules are quite clear so I am not surprised that you were unable to persuade a member of the CS team to alter the computer-generated assessment.