A WebmasterWorld member reports that he was dependent on the Top Search Queries report in Google Webmaster Tools and has found it to be providing incorrect data. After all, using another rank checker proved to see no results and there were no visitors to that page.

This is likely to be a bug, according to Tedster:

He adds that it’s possible that the ranking is achievable:

Still, though, the tool in Google’s backend is misleading.

Would you consider this a bug?

On a related note, The Official Google Webmaster Central Blog says that this could be an issue with the kind of data that WMT sees. They suggest that you add the www and non-www versions of the same site to Webmaster Central, do a site: search to look for any anomalies, set your preferred domain, and set a site-wide 301 redirect to www or the non-www. Of course, this is probably not applicable to the reporting issue in WebmasterWorld, though it may be related to other issues within Google Webmaster Tools.

Forum discussion continues at WebmasterWorld.