How to render facet blocks?

Hello community,

I'm re-building a D8 site with latest backdrop cms. "Key feature" is a facet search.
Installation and configuration has adavanced smoothly until now:

When trying to put the facet blocks into my layout, those facet blocks appear in the block selection list, they can be put into regions, but after saving the layout and viewing the page – the blocks don't show up...

Theme is "Basis", layout is "Home page".

Any idea what I am missing or doing wrong?

Thanks in advance and best regards