search results are awry

Using RoboHelp for HTML 5.0.1. Problem: I search for a word or a phrase using the keyword search in the output help files. Some of the suggested topics do contain my search term. Others do not. They don't contain anything even close. Nothing similar in underlying code (the wysiwyg i.e.). I can't spot a pattern -- it's not any given phrase or phrases that fail to show. All are common English terms -- no oddball punctuations or spellings etc. We used to see this on rare occasions, but it seems to me to be increasing in frequency. Others see identical behaviors on their machines. Help is served on a network..

Thoughts? I guess I could understand valid topics being omitted more easily than this situation of inappropriate ones being included.