Most likely your park tickets were not linked to the same MDE profile as your hotel reservation.
Tickets and hotel aren't directly linked to specific Magic Bands. Instead, everything (Band, ticket, hotel reservation, FP+, etc) is linked to your profile in the MDE system. They all interact with each other through your central MDE profile. When you link a purchased Band in the park, the CM uses something already linked to "you" (a ticket, another Band) to then link the new Band to "you".
The problem is that if everything isn't all connected to the same profile, they can't talk to each other.
So if you bought the tickets under your home email address and booked the hotel under your work email, they don't see each of them as the same person. Or perhaps the hotel was booked by someone else and the "you" on the hotel reservation is a sub-profile on *that* person's account.
-Rob