Bug in challenges pages?

Logged in. Go-to home page. Hit challenge caches link. It shows 20 in the list, and says there are 42. Hit page 2. Gives:
Site Error
Something went wrong. If the error persists, please contact the site admin.
Page: search2.php
Information Message: The retrieval query could not be implemented, enter search data again.
Site Error
Something went wrong. If the error persists, please contact the site admin.
Page: search2.php
Information Message: The retrieval query could not be implemented, enter search data again.