I received a reply from Pearson - looks like the answer will count after all.
Candidate Services, GMAT Americas <gmatcandidateservicesamericas AT pearson DOTCOM>
Tue 2017-03-07 1:25 AM
Thank you for contacting Pearson VUE GMAT Customer Service.
All information entered into the exam prior to the exam timing out is scored.
If you have any further questions or inquiries, please contact us again.
With Kind Regards,
Chetna C.
GMAT Americas Customer Service Team
Customer Support Specialist
Pearson VUE
To: GMATCandidateServicesAmericas AT pearson DOTCOM
Subject: GMAT: Run Out of Time Before Confirming Final Response
On the GMAT, if I am on the last question of a section, and I select an answer, but run out of time before I can confirm it, what happens? Will the response be recorded or will the question count as unanswered?
I have seen conflicting posts on forums about the GMAC's official response to this question, so please investigate and let me know the correct answer.
Thank you very much.