The other possibility is that at the time of the ajax request that ACF/WP does not know what the post ID is of the post you’re checking the other values on. This may or may not be available. It will certainly not be in the global $post as this is not set during an ajax request. To be honest, now that I think about this, the current post ID may not event be available during the acf/init hook, depending on what admin page is being loaded. How are you getting the post ID to check the values of the other fields?
