It must be another glitch with the system being terrible lately. They should be bankable according to the terms in the home resort rules and regulations once you cancel/opt out of the guaranteed week.
"12. Home Resort Vacation Points related to a Fixed Ownership Interest may not be Banked, Borrowed, or Transferred unless the Club Member has opted-out of or cancelled the Club Member’s Guaranteed Reservation for the Use Year during which the Club Member intends to use the Home Resort Vacation Points for such other purposes. If, in any Use Year, a Club Member wants to Bank Home Resort Vacation Points into the following year, the Club Member must first opt out of the Guaranteed Reservation for the current Use Year. If, in any Use Year, the Club Member wants to Borrow Home Resort Vacation Points from the following year, the Club Member must first opt out of the Guaranteed Reservation for the following Use Year. If, in any Use Year, the Club Member wants to Transfer Home Resort Vacation Points, the Club Member must first opt out of the Guaranteed Reservation for the applicable Use Year."