I ma having some success with WP Rocket. With the options I have selected the issue I can see is that the mobile menu button behaves strangely when first accessing a page.
The Hamburger and text jumps below the icon on the left instead of aligning right. It sometimes starts like this and then reverts back after a scroll down and then up and sometimes it starts fine and then goes below the logo after scroll down and then corrects itself when scrolling up. Images below highlight the problem.
I am aware that this is not a generatepress issue but wondered if anybody had any thoughts on how to solve. Maybe a setting change in WP Rocket.