Sounds like OPB is trying to reroute some aircraft. When they do this, even if they aren't 100% sure of the final schedules/routings, it often causes availability to go haywire. Theory is, it is better to have the smaller plane in the schedule for a short time and not sell any seatsm then to compound the huge possible oversale by continuing to sell during the time they are fidgeting with different aircraft/route combos.