Plugin breaks The Events Calendar javascript

(development website HTTP auth: username bbuzzdev, password 97493ef4)

I’m using The Events Calendar Community Events plugin (a paid plugin) which allows external users to create events on our website via a form at the link above. You will need to create an account to list an event – please go ahead and do so if you want to see this problem actually occuring.

The UI for adding recurring events was broken, so I deactivated plugins until I found that “External & Affiliate Links Processor” was causing the issue.

When your plugin is activated, the following errors appear in the JavaScript when the “schedule multiple events” button is clicked:

events-recurrence.js?ver=4.4.32:770 Uncaught TypeError: Cannot read property 'toLowerCase' of undefined
    at Object.my.update_rule_recurrence_text (events-recurrence.js?ver=4.4.32:770)
    at HTMLInputElement.my.event.weekdays_changed (events-recurrence.js?ver=4.4.32:1099)
    at HTMLDivElement.dispatch (jquery.js?ver=1.12.4:3)
    at HTMLDivElement.r.handle (jquery.js?ver=1.12.4:3)
    at Object.trigger (jquery.js?ver=1.12.4:3)
    at Object.a.event.trigger (jquery-migrate.min.js?ver=1.4.1:2)
    at HTMLInputElement.<anonymous> (jquery.js?ver=1.12.4:3)
    at Function.each (jquery.js?ver=1.12.4:2)
    at a.fn.init.each (jquery.js?ver=1.12.4:2)
    at a.fn.init.trigger (jquery.js?ver=1.12.4:3)

The relevant lines of TEC Community Events’ javascript seem to be:

var end_type  = $rule.find( '[data-field="end-type"] option:selected' ).val();
end_type = end_type.toLowerCase().replace( ' ', '-' );

(the second one of those being the one with the error)

That’s about as far as I was able to dig, but I am guessing that your code is replacing something in the guts of the TEC code that is breaking things. Are you able to help me?

Regards,

Alex

The page I need help with: [log in to see the link]