Why does the content I pasted into my incident thread save with question marks? 

Environment:

Oracle B2C Service, All supported versions

Resolution:

Many fonts are supported by the B2C Service application. However, you may run across a unique font we do not support. This can occur when you copy and paste content into the incident, opportunity, task, or answer workspace. At the point the record is saved, and the system doesn't recognize the font, it will replace the content with question marks. 

For best practices, if you are using a unique font and pasting the content into an incident response as plain text does not transfer it to the default font like other characters you have typed into the field, then you can create an image of that unique content and include it as an image. This may happen with scientific documents with math equations for example. When sending those responses, be sure to review the response after clicking Save to make sure the content was saved in the incident thread as expected. 

Additional details: 

Answer ID 6165: Adding my own specific font to the list of available fonts for incidents