Hello rhythmtravels,
I apologize for the delay with this issue.
You can remove the plugin now, I was able to pass it onto our developers to get check the information we were looking for.
Since this is an issue that requires extended time to check for conflicts, would it be possible for you to setup a new site on your current hosting configuration that is a stripped down site of just the Events Calendar plugins and default theme? Set it up with the same Facebook import settings and see if you get the same import duplication on that stripped down site.
I apologize again for the inconvenience.This one has just been a struggle to test since we’ve been consistently unable to replicate under various hosting and configuration conditions.
Thanks!