Hi,

With Guix at b7078d5d49d72cb5e5356d698b99540612b4d6c4, I tried to
reproduce the issue, but I didn't get any error.

I started FreeCAD with:

--8<---------------cut here---------------start------------->8---
guix shell freecad openscad -- FreeCAD
--8<---------------cut here---------------end--------------->8---

Then I selected "OpenSCAD" in the box, then the "OpenSCAD -> Add
OpenSCAD Element" menu item, then I typed "cube();", clicked "Add", and
it created a cube without any error message (I tried with the "mesh" box
ticked and unticked).

Can you still reproduce the issue on your side?