Hi Jovan,
Seems like there is some conflict with other plugins. Any chance you deactivate others and see if that helps ? Later can activate one by one and know the culprit and search solution as per it.
Regarding the database, we store our font information in {tablePrefix}_options table. And the option key used are
uaf_api_key
uaf_server_url_type
uaf_activated_url
uaf_site_url
uaf_uploader_type
uaf_font_display_property
uaf_enable_multi_lang_support
uaf_disbale_editor_font_list
uaf_use_absolute_font_path
uaf_hide_key
uaf_font_data
uaf_font_implement
Bold ones are those storing font and font assign record.
Thanks