There seems to be a conflict with Polylang and the Header Builder.
When I build a Header with the Polylang Plugin turned on; my Header won’t display on the front end.
If I turn off the Polylang Plugin first, and then make the Header, all is well even after turning the Polylang Plugin back on.
My header and Polylang are currently working (currently), I thought I’d bring it to your attention.
MikeL