[Tex2002ans]

I'm 99% sure you have Soft Hyphens hidden in your code.

Easiest way to find it is:

1. Tools > Reports > Characters in HTML Files

This will give you a list of all characters in your book.

2. Scroll down the list and look for anything strange:



3. Double-click the row, and it will put the strange character in the Search for you. You can then Find/Replace.

In this case, if you double-click the Soft Hyphen, you can then replace it with nothing.

Note: I attached a sample EPUB with a soft hyphen in it.

<p>This example has a soft hyphen.</p>

In the EPUB, the word "example" has a soft hyphen between the ex-ample.

Note #2: If it isn't a Soft Hyphen, then it's probably one of the many different types of spaces or invisible characters (like a Zero-Width Joiner). Those will all show up in the Report.