We ran into this issue while upgrading the blog factory from 3.0.1 to 3.4 and we have a simple solution. The issue was with the javascript files, and for some reason, we started to try to troubleshoot. and we found out to Just copy the default Joomla Joomla_dir/media/editors/tinymce/tinymce.min.js file into joomla_dir/components/com_blogfactory/assets/js/tinymce/ folder
make a backup of your old JS file in case anything happens.
Enjoy!