Hello,
Your bottom header bar is empty in mobile header layout. If you want to display the bottom header bar in mobile and want to make it sticky, then first you have to use some elements inside the bottom header row from WoodMart >> Header Builder >> Your default header >> Switch to mobile layout.
Screenshot for clarification: https://jmp.sh/XEje3Kn
In case if you want to achieve something else, then share the screenshot by pointing the specific section.
Best Regards.