Warnings after start using Elementor & Sidney theme

I started using Elementor since a few weeks to improve my personal Web site created with Sydney theme (www.nicolamuraro.it).
Now I have issues I did not face before.
While opening the home page the following warnings are shown:
“Warning: mysqli_num_fields() expects parameter 1 to be mysqli_result, boolean given in /web/htdocs/www.nicolamuraro.it/home/wp-includes/wp-db.php on line 3353
… document.addEventListener(‘touchstart’, onTouchStart, {passive: true});”
The warnings do not stop pages loading, but clearly they are not acceptable.
I do not know if it depends on Elementor or not, of if there is a known conflict among Elementor and others plugins.
Anybody faced same or similar issues?
How is it possible to fix them?
Thank you advance for any help coming from you, my friendsWarnings.