Hi,

1) Here is some extra CSS to fix the sticky header shift:

#header.container.tbSticky:not(.tbStickyScrolled), #header.tbStickyScrolled.tb_sticky_width_fixed,
#sticky_header.tb_sticky_width_fixed
{
  left: 50vw;
}

Add these styles from the Theme CP > Theme Settings > Custom > Custom Stylesheet text field.

2) If you have the cache option enabled, you need to clear it every time your menu is updated.

BR,
ThemeBurn team