Hello again,
I checked the theme and child theme you sent in a local environment and all was working fine.
Since I don’t know your theme settings, it could be something there, or how the single event page is set up, or some other plugin is messing with the page. It looks like most of the page is loaded, then somewhere at the end the extra buttons are added to the code, I suspect via some jQuery or javascript.
A next step would be running a text for conflicts based on this guide – after disabling the css code for hiding the buttons. That should help us find any misbehaving plugins.
Since all seems to work fine with a default theme, and the issue appears with Avada, your other option would be getting in touch with the Avada developers to take a look at it.
I’m sorry I cannot give any solution to this, the source of the issue pretty hard to nail down. I’m happy to help you further in finding the source of the issue, just let me know and we go step by step as results come in.
Cheers
Andras