Yep, we go several times a year, and the dining reservations page works about 50% of the time. Including all my reservations will show on Monday...be gone Tues-Thurs, show up again on Friday, then I'll get the error message about "unable to display dining reservations at this time" all weekend. Happens often enough to know it's just their system.
Now I just load the restaurant name, ADR time & confirmation number on my google calendar, which is linked to my phone. That way I always have all the details with me. And I get a nice little reminder from my phone on the day of the reservation, too.