Hey John!
The good news here is that this is not an “error” notice – nothing is broken on your site, in other words (at least, this message does not indicate such).
This message is posted by The Events Calendar if you have the “Debug mode” option checked in your Events Settings page.
To disable this message, go to Events > Settings and un-check the “debug mode” option like in this screenshot:

Save your changes; if the error keeps showing up, then there might be a server-specific configuration that is causing this to display, so your best step from there would be to contact WP Engine support and tell them how the logging persists even when you disable it in the plugin.
I hope this helps!
George