To add another data point to yours, I checked last night around 11 p.m. my time (2 a.m. east coast time) just
in case there was a glitch in the matrix & the start dates after 1/28/26 were still greyed out. This morning at 7:55 a.m. eastern time I tried booking a reservation for 1/31/26 & was able to select my start date + 8 nights but then ran into the “wait until 8 a.m.” message.
I know nothing about tech & have little faith that Disney’s tech is unreliable in a predictable/explicable way, but maybe it depends on how many times you try to book in the same session (first time you try you get a wait until 8 & after that you just get a general error message) or maybe it depends on how close to 8 a.m. you are trying?
The one positive about booking for a stay starting in late Jan. was that I was able to get all 8 nights of my reservation this morning rather than my usual 11 month dance of booking 7 nights then adding on my extra nights a few days later

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