OK – we need to do one thing that might resolve this but needs to be done before we can investigate any further. nd we will do this the quick way first. TinyMCE needs a Farsi language file and you do not have one in the base install. So for now can you please do the following – and I am afraid you will need to do this in 3 places.
Locate the file called en.js is the following three folders and COPY it to a new file called fa.js.
The three locations are:
wp-content/sp-resources/forum-plugins/tinymce-richtext/inymce/langs/
wp-content/sp-resources/forum-plugins/tinymce-richtext/inymce/plugins/spoiler/langs/
wp-content/sp-resources/forum-plugins/tinymce-richtext/inymce/themes/advanced/langs/
Then go to the forum admin > components > Editor and change the timymce language setting from ‘fa_IR’ to simply ‘fa’.
See if that helps at all…