Just running some tests, and came to an interesting error. Searching for "Avengers", which says it yields 417 results, I can get page through the results, but on the last page, 5, using this URL:
it gives a "HTTP Error 500 (Internal Server Error)". It's pretty consistent. I have been seeing intermittent timeout errors with other requests, but I assume that's just the backend doing some caching. This looks like something different.