Yeah, I had the same problem recently.
Searched for LAX on 17-JAN and the Renaissance didn't show up (neither did the Marriott). When I searched Google for the Renaissance, then clicked through to that hotel's page, I was able to book (and they had a large selection of rooms available).
Same for Hong Kong, the Renaissance didn't show up in the results when searching 19-JAN (neither did St. Regis). I went to that hotels page (from previous stay) and was able to book (again, large number of rooms available).