This is more of a feedback than a problem as I worked it out myself, but I thought maybe it is worth sharing.
I was adding HTML symbols to my menu links in WB in the admin backend, using the code ⇣ to display a down arrow as a character in the parent menu text. When I decided to change or remove the HTML code, I was getting some broken links to the pages that were using the code in the website menu. I found that the property File Link in the Modify Page subsection under Change Settings had kept the HTML code, even if I removed it from the Menu Title.
I had to use my FTP to remove the code from the page name in the /pages directory (including any folders using the same name due to having child pages).