During troubleshooting, I noticed that the form "Job Posting" seems to be configured correctly and it is strange that validation message shows, even when the fields have values.
Do I have your permission to download a clone/snapshot of your website? This will allow us to investigate this in more depth on a test server.
Yes, you have my permission to clone the website for further investigation. If you need additional information from me please let me know. I appreciate your help.
Waqar, thank you. Enabling the "Submit this form without reloading the page (use AJAX)" option seems to have resolved the issue. I have successfully submitted the form.
I should have guessed that it was The Events Calendar causing a conflict, even though these forms don't interact directly with any calendar functions. Their suite of plugins (The Events Calendar, The Events Calendar Pro and Community Events) have not interfaced well with your plugins (Layouts in particular) and it's been a constant battle with this particular site which is heavily dependent upon both.
I wanted to let you know that the latest releases of Toolset plugins include a fix for this issue.
If the updates do not show up on your plugin installer page (click the registered link beneath the plugin name to go to the custom installer page) click the 'Check for Updates' button to update the list.