Just letting you know in case you can replicate this on your demo site... I just edited an existing event as a front-end user... and the site admin got sent an email saying a New Event had been created (the one I'd just edited)
Yes Andy, I'm able to replicate the issue now I've logged this issue in our issue tracker and our developers will take an action for this.
Just to help you see if you can replicate it... the email subject title was correct (it said Event Updated)... It was just the email body that had the 'New Event Created' wording throughout it.