Cannot mesh geometry with free face

I ran into a problem meshing geometry where a thin volume is replaced with a face. This might save a lot of computation efforts, but it seems that netgen fails to mesh such geometries.

I am using OCCgeometry. The used BREP file is attached.

When using netgen/ngsolve interface, meshing fails with errors

GIVING UP retry Surface 21 Face 21 / 21 (plane space projection) meshed area = 0.0200098 maximal area = 0.02 GIVING UP ERROR: Problem in Surface mesh generation WARNING! NOT ALL FACES HAVE BEEN MESHED SURFACE MESHING ERROR OCCURRED IN 1 FACES: Face 21

I also tried meshing manually - first meshing with nglib all the faces, then merging them into volume and meshing volume. Such an approach works for other geometries, but not for this one. Error is “Stop meshing since surface mesh not consistent”.

Is there a way or strategy to mesh such geometries?

Apparently attachments are missing. Adding here

Attachment: test_free_face_2020-12-07-3.brep