There are a couple of reasons this could happen:
If a cache is enabled for logged in users then changed pages will not show up properly. This means that the guest user will not see the submit-ticket page when it is changed. Please contact your host and ask them to update the cache configuration to make sure that when users are logged in no pages are cached.
Check your browser console to see if the following message (or similar) appears: Strict-Transport-Security: The site specified a header that could not be parsed successfully. You might also see a reference to submit-ticket and admin-ajax.php.
More information about HSTS can be found here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security