Many have reported strange availability issues the week of June 13th in MK and AK. Initially, no dinner reservations were available after 6pm for any of the in park restaurants (at the 60+ dates). Some have since opened up— the theory is they auto-populated the reservation availability with last year’s times and it was not resolved for several days. This is not scientific, but my guess is that when folks saw no ADRs available for dinner they panicked and snatched up whatever they could get. I suspect that as dates get closer people will be dropping reservations after securing their preferred restaurants or times— this may be impacting Crystal Palace availability.
You might try using a reservation finder for Crystal Palace — I have been seeing many folks post that they’ve been able to secure their preferences with these 3rd party alerts when reservations do open up. Good luck!