Hi, find different menu module on JED that is MegaMenu type and use it. Otherwise you have to use custom CSS or Boostrap classes fo navigation.

To be clear this is not SPPB issue, and never was. Joomla display menu this way by default.

If your template use boostrap 4 - use those class names from: https://getbootstrap.com/docs/4.0/components/navbar/

Or as I said before just find ready MegaMenu module and publish somewhere.

Thank you, it helped and everything worked as it should!

You're welcome.