Look at this post in the Civil Aviation Forum:
Now, try to search the Civil Aviation Forum using the words "Buddy Holly" with "Subject" and "Message Body" checked, and "Last 2 weeks" and "All Words" selected.
You should definitely get the above post as a result, since that post had the words "Buddy Holly", yet, I see no results.
Who knows what other search results might be failing as well?
Can you investigate?