Hi Antonios,
I’m sorry you are having this issue with the attendee information fields. Let me try to help you with this.
I quickly tested this on a local install with only our plugins and Avada, and couldn’t reproduce it.
Could you please run a test for conflicting plugins / theme? Here’s a guide how you can do that:
Testing Conflicts With Themes and Other Plugins
Basically what you need to do is deactivate all plugins except for the Modern Tribe ones and the core WooCommerce, and switch the theme to twentysixteen and check if the issue exists.
If the issue is gone, then switch back your theme and check.
If still no issue, then activate your other plugins one-by-one and check after each to see which causes this glitch.
Let me know the results.
Thanks and cheers,
Andras