Are you sure it is the confirmation from Interval International that indicates a $25 fee? Perhaps it is the confirmation from Marriott.com that you received if you added your Bonvoy number to the reservation? Looking at an II confirmation from Harbour Lake for January, I just see the generic fee advisement;
Resort parking is typically limited to one car per unit. A parking fee may be charged. Some resorts may have no on-site parking, requiring the use of an alternate off-site facility at an additional fee. Prior arrangements must be made for parking trailers, boats, motorcycles or any type of recreational vehicle (may not have on-site).