I finally found the solution. What was missing in search was “topic” (Debates in spanish), so now it's working as expected. So the text that was wrong now is displayed as should be (green arrow). Also it changed the order, before was the first result and now is after the blog posts, so the topic and its replies are together at the end of the results.
About the Firefox issue, you were right. I cleared the cache and now it woks as the other browsers.
Thank you very much!!