Hi,
Thanks for using our plugins.
I loaded up that plugin and did not get those messages and checked and the plugin did add the meta tags.
Our plugin by default does not add any of those meta tags those errors are showing.
It is possible it could be added through your theme or another plugin or through a customization of the Events Calendar.
However, checking on my site with Pro active no Facebook Open Graph Tags are added.
Let me know if you have any follow up questions.
Thanks