I am talking about addon searches. I do not get it every single time but often enough for it to be annoying. I'll try to reproduce right now and submit a screenshot. One sec...
Here we go.
For example, I click on advanced search. I type in spam. Then I check Mists of Pandaria ready and I also check title as well as description. I hit search and I get 4 pages of results. I click on page 2 or 3 and this is what I'm getting:
It seems whenever I'm doing an advanced search with something more than title checked, that gives me more than one page of results, it spits out an error.