Hey Laura,
Thanks for reaching out! I tried this on my computer, have the same version of Edge and I don’t get this error. I have a basic WP install 4.6.1 with only Modern Tribe plugins activated and the visual editor shows up just fine on the Community Events > Add Event page.
From your opening post I don’t quite get it if you need help with this or not. 🙂 In case you do, then please read on. 🙂
Would you mind running a test for conflicts? Basically you need to deactivate all plugins (except for Modern Tribe ones) and switch to a default theme like twentysixteen. And check whether you still have the issue.
Here’s a full guide on how to test for conflicts if you need more details:
Testing Conflicts With Themes and Other Plugins
Thanks and cheers,
Andras