ambienthack

In my case ACF broke standard WYSIWYG editor, but WYSIWYGs of custom fields worked fine.

For me the solution was to add one line in advanced-custom-fields/core/fields/wysiwyg.php.

After line -> $(this).find('.acf_wysiwyg textarea').each(function(){
Add -> if ($(this).filter(':hidden').lenght) return;