Custom Theme WPForo page throwing TinyMCE error

Hi,

I'm new to WP development, but I have a lot of PHP experience. My question is probably easy, but I don't know the WP framework very well yet.

I have created a custom theme, and the wpforo shortcode is displaying the forums well.  However, TinyMCE is throwing a console error and preventing any post creation.  Under a different theme, the forums do work. 

I've ensured WPForo is up to date.  TinyMCE isn't a plugin under my admin plugins section, but I do see that the code is present in the wp-includes folder as expected. 

Any suggestions on how to proceed?  I don't even know what to check at this point. 

Much appreciated.

tinymce.min.js?ver=4960-20190918:2 Uncaught TypeError: Cannot read property 'apply' of undefined
    at tN.execCallback (tinymce.min.js?ver=4960-20190918:2)
    at new tN (tinymce.min.js?ver=4960-20190918:2)
    at n (tinymce.min.js?ver=4960-20190918:2)
    at Array.<anonymous> (tinymce.min.js?ver=4960-20190918:2)
    at qt (tinymce.min.js?ver=4960-20190918:2)
    at Object.e (tinymce.min.js?ver=4960-20190918:2)
    at C (tinymce.min.js?ver=4960-20190918:2)
    at d (tinymce.min.js?ver=4960-20190918:2)
    at a (tinymce.min.js?ver=4960-20190918:2)