Accidently posted before I finished... not exactly sure but as best I can understand, it was not the latch that folds the rear seat down but the one underneath the seat. It was causing the entire rear seat to wobble a bit, causing the knocking sound. Sorry if I'm not explaining it exactly right.
I just wanted to post this FYI in case anyone has the same issue. '24 Integra had a knocking sound coming from below or behind the rear seat at slow speeds over bumps starting after 1 year/22K miles. Brought it to dealership and they said it was the can of fix-a-flat rolling around in the...