Hi Philip and welcome to the forums! Sorry you’re hitting some trouble here with recurring events on your site, but hopefully we can figure out what happening here together. 🙂
First off, are you using the latest versions of the plugins? Please update The Events Calendar, The Events Calendar PRO and Facebook Events to version 3.9.1 and see if this helps resolve the issue.
I recall a similar issue to this a while back and it was the result of a conflict with another plugin. I see you noted the following:
Deactivated all other plugins? Yes
Switched to a default theme? Yes
Did you notice any difference under these conditions? How about if you deactivate all other plugins while using a default WordPress theme, like Twenty Fourteen?
I notice that you are using the WPML plugin and there are known conflicts with that and our plugin that can cause this sort of issue. It would be super helpful if you could try deactivating it while following the steps in our Testing for Conflicts Guide to see if that same conflict is hitting you as well.
Let’s start there before we dig any deeper. Please gives these things a shot and let me know what you find. 🙂
Cheers!
Geoff