I see the one week that you noted for next October but the next earliest date is October 7th. This late October week may be an owner deposit since it appears to be out there on it's own.
It appears that Marriott is bulk banking a lot of unsold inventory, and off season, August though November in South Florida is off season. Oceana Palms has a lot of unsold inventory, so this isn't unexpected. It seems that Marriott may be getting a good handle on what they think they will need for DC and are now bulk banking about two to three months after the initial booking window opens. I expect to see more of this going forward and I think this is a good thing for those of us that still wish to use II for our exchanges.