Can you let me know what changed exactly?
Currently I only see the header and footer coming from GP and the content is all from Elementor which GP doesn’t have any control.
As for the error message from Elementor, have you tried their suggestions here?
It’s unlikely that it’s a theme issue as lots of our users are using the current version of GP and Elementor without this issue.
Might be worth disabling all other plugins to test if there is a conflict.