I haven't experienced that. We've got a cruise booked for October 2025 and I made our dining reservations for DMW the same day(9 April 2024). On 15 April I received an Email from Princess those reservations will be deleted by 17 June due to the new MDR schedules. Starting with voyages departing September 14, 2024, Princess will designate separate dining rooms aboard every ship in the fleet to three table service options: Traditional dining offering an early and a late seating every evening, reservable dining times, and open seating to support walk-ins anytime. I'll rebook DMW at that time. Maybe what you are experiencing is due to the upcoming change (?).