If you locate strange symbols in the fact value of your tagged note, you will also have the warning FactsWithNonDisplayableCharacters in your Validation report. If your Validation report contains the warning FactWithNonDisplayableCharacters, then it means that part of the text included in a specific tagged location has not been correctly transformed. The issue occurs during the PDF to xHTML conversion where some characters are recognized incorrectly, meaning that there is a graphical issue (Something we call as 'Unicode')
You are able to confirm this by checking the fact value found when selecting the element present in the FactWithNonDisplayableCharacters warning in the Viewer tab or the Facts tab in the ParsePort Platform. To solve this issue, you will need to assess how your visual component (PDF) has been created. Some features used in a design software such as InDesign work perfectly fine for a PDF but not for an xHTML format. Examples of these are Ligatures or OpenType fonts.
For more information check this article: FactsWithNonDisplayableCharacters warning, what can I do?