Thanks for your prompt reply!
I’m referring to the WordPress Navigation Block. (Not pagination/arrows within Gutenslider, but I just turned those on for the sake of argument.)
Here’s a page with the stock header, set to use the mobile menu. Mobile nav toggle (i.e. hamburger icon) works. https://cbtest.instawp.xyz/index.php/sample-page/
However, the same mobile menu hamburger toggle, placed over a “fixed” Gutenslider, doesn’t activate. (The Hamburger icon is just to the right of the logo, in this example.)
Perhaps I’m screwing something up somewhere, but I’m very grateful for any insight you may have!