I had exactly the same problem and managed to track it down to some theme code.
I used a bone theme that unregisters jQuery JS by default and adds my own using Google CDN, for example:
// we don't need the Wordpress jquery as we are loading our own version add_action('wp_enqueue_scripts', 'stnic_remove_jquery'); function stnic_remove_jquery(){ if(!is_admin()) { wp_deregister_script('jquery'); } } // loading modernizr and jquery, and reply script function bones_scripts_and_styles() { if (!is_admin()) { wp_register_script( 'cdn-jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js', array(), '', false ); } }
As you can see, it deregister is the default jquery script, and then it adds its own cdn-jquery script, which is good, besides the fact that Gravity form scripts are dependent on jquery and not cdn-jquery !
Since they cannot see the default jquery script, they do not load, and it may appear that they silently fail, simply throwing this JavaScript error, because the specified JavaScript loads without dependency checking.
In any case, I fixed this by renaming the bone registration script in jquery , maybe this is not the best way to fix it, but it works.
In addition, commenting out both code snippets will also fix this (and leave Wordpress JS installed by default).
Not sure if other topics do this, but it might be worth a search on your entire topic for wp_deregister_script('jquery'); or at least switch to the default theme to see if you have the same problem (exactly as I defined it).