I’m having this same issue. When I have a custom field that is an image upload, it gives me the following error:
post.php?post=4&action=edit:4035 Uncaught ReferenceError: acf is not defined
at post.php?post=4&action=edit:4035
(anonymous) @ post.php?post=4&action=edit:4035
input.min.js?ver=4.4.11:1 Uncaught TypeError: Cannot read property 'post_id' of null
at HTMLDocument.<anonymous> (input.min.js?ver=4.4.11:1)
at i (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,jquery-ui-core,jquery-ui-widget,jquery-ui-mo…:2)
at Object.fireWith [as resolveWith] (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,jquery-ui-core,jquery-ui-widget,jquery-ui-mo…:2)
at Function.ready (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,jquery-ui-core,jquery-ui-widget,jquery-ui-mo…:2)
at HTMLDocument.K (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,jquery-ui-core,jquery-ui-widget,jquery-ui-mo…:2)
