“undefined” message after application has been submitted

You can see this error when you try to “post a job” here: https://jobs.chicktech.org/
The jobs don’t post, and we get an “undefined” message at the top of the screen.

Chrome dev tools notes this error:
plugin.min.js:1 Deprecated TinyMCE API call: <target>.onChange.add(..)

This plugin came bundled in a theme by Engine Themes.

Your help much appreciated.
thank you!