Hey Scott,
Thank you for reaching out to us!
I’ve ran some tests in my own WordPress install (with all Modern Tribe plugins installed and Twenty Seventeen theme) and wasn’t able to reproduce the error.
Could you please make sure that Community Events is up-to-date? The latest version is 4.5.6.
If you disable the “Use visual editor for event descriptions” on Events > Settings > Community and try to submit a new event (with a description), is the problem solved?
When you enable WP_DEBUG and WP_DEBUG_LOG, do you see any errors? All WP_DEBUG messages will be stored in a debug.log file in /wp-content.
Thanks!
Patricia