MDE is notoriously buggy and does what it wants.
If you have your confirmation numbers (and/or e-mails) then you are fine.
I've only ever had to produce a confirmation number/e-mail once, and we got seated shortly thereafter. In a couple of other cases on recent trips, the restaurant had our ADR even though it didn't show in the MDE for us.
I have a list of every reservation (some copied and pasted) complete with date time and confirmation number. That includes events (BBB etc), dining, resort, photo pass (or whatever they call it now) everything.
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