RoboHelp 2019 Responsive HTML5 returned results not accurate

I have over 18 topics in my project. I generated the output and performed search for a word that I know exists in 15 of the 18 documents. The search result only returned 3 topics. When I did the same search using find (Find and Replace) in Author mode, all 15 documents appeared in the results of the find. Is there something that I need to do, short of creating a filter by keywords, to show the expected result; I do not always know what keywords users will be searching for.