Adding keywords to a topic causes search to return file names instead of topic titles

When I search for a term in my WebHelp Pro project, the topics returned are shown by file name if the topic has anything in its Properties > General > Keywords field and are shown by topic title if there are no keywords defined for the topic.

I've confirmed this behavior by adding and removing keywords from topics and watching them alternate between being shown in searches by file name or by topic title.

Obviously, I want topics to be displayed by topic titles in search results no matter if they have keywords assigned or not.

Any idea what would be causing this? Is this a known bug?

Here's some additional information. For this problem to occur, these four conditions must be true:

1. The topic must have manually added keyword(s) in the Properties > General > Keywords field.
2. The topic title and the file name must be different.
3. One must be searching for one of the keyword(s) added in step 1.
4. Occurs in WebHelp Pro when published to a remote server.

Talks with Adobe today are inconclusive but it appears that this was an unknown bug. Maybe I'll get a free t-shirt or something.