Import file, add to scene, shows no result

working since years with Nomad on Galaxy tab S7.
One of my processing is to construct an exact Object in a 3D cad programm and then import the STL file for free sculpting in Nomad and then print it.
Suddenly, the import of a STL or OB] file, add to scene, shows no result, the object of the file is not visible and does not even show in the object list.
But the same 3D cad STL file works in the 3D printer slicer SW .
Even older STL files, which I could import before are not working any longer…

Is this a known issue with a solution?
Could not find something about itin the Bug report section

Thank you for any response