Hey Carl,
This unfortunately seems to be caused by a theme or plugin conflict, which we may not be able to help with much, but can you first try this:
• Deactivate the plugin on your site called “Templater” or something similar. I see a script coming from a plugin named something like this, the script is producing a console error and it could be the problem.
• If deactivating that plugin alone does not help, proceed with all of the other steps here → https://theeventscalendar.com/knowledgebase/testing-for-conflicts/
Let us know what you find!
Thank you,
George