Hi there,
GeneratePress sticky menu is not working properly
Can you give us some more details?
As a general note Parallax backgrounds can put a lot of strain on the browser and the device, as it requires the viewport to be re-rendered over and over again when the user scrolls. In addition it uses Javascript to detect the movement. All of these things combined can lead to a ‘laggy’ experience and effect other elements that are repositioned using JS eg. the Sticky Nav.