>>IIRC a user can override font style in Firefox by creating their own 'userContent.css' file.
>>At the end of the day all browsers are capable of overriding site settings if they so wish.........
>
>We double checked with the user and the settings are all default. There is no overwrite. However, the font is not the same. I am trying to figure this one out as to know what is causing this.

Did you check that one of the listed fonts was installed ?