Yeah, i had the same problem with the Organic overlay header, and solved it like this:

– Edit the Main Header settings (the little pen that comes up next to Main Header) under Colors to display the Dark text color scheme, and set the BG color to White. Save.
– Then open up the BG color settings again, and delete the BG color you’ve just changed. The overlay BG goes back to being transparent, but white remains the BG color of the sticky header. Save. Fixed.