Yeah I was getting the same issues on the app. After many times calling over the last few weeks and getting agents unwilling to dig further, I finally got somebody today who took some time to try and figure out -- mainly because she was a tenured agent and was getting the same errors on her end which she had never seen before.

From what we could gather after she looped in a higher tier support colleague and the property directly, there's some sort of bug in the system where the reservation engine basically kicks an error and fails the search because it thinks one of the nights isn't actually available on any award, even though the flexible dates calendar shows there should be availability and even if you search for that one night specifically there is availability. We couldn't quite diagnose why it was only happening with this property in particular (after all - if this was a wider issue it likely would have been brought up by others). Eventually we were able to make it work with dates that returned positive base-level availability on all 5 nights but it took a lot of back and forth with date checks.

Incredibly frustrating because if I went and booked each night separately I would be able to make it work, but it would require a 5th night "penalty" since the free night wouldn't apply as it would on a normal single reservation for 5 nights.

I would invite others to try booking the same dates where I receive errors and see if they also receive the same. Try 10/31 - 11/5 or 10/30-11/4 to receive an error, but then try checking each of those dates individually (they all have the base garden view room available). Then alternatively, try 11/6 - 11/11 to see results and pricing actually populate correctly for the 5 night stay (346K at this point in time, with 5th night free)