Salome crashes after computing mesh with modified group


I am new to Salome, and I am experimenting on how to create/modify meshes using Shaper and Mesh modules.
I got a problem, when after some group modifications in Shaper, the program crashes when computing the mesh.

I started with a simple plate made on Shaper:

And a mesh made using that plate, and a submesh using one edge (to define the number of elements on the thickness).

All this is contained in the .hdf file attached
test_plate.hdf (291,4 KB)

After that, I modified the group, adding to it a second edge to it, and computed again the mesh.

I went on and modified the group again, adding a third edge

But after I clicked on Compute, the program froze for a few seconds and then crashed without any message.

Why does the program crash?
How to avoid it?
Is there any record of what the error might be?

Thank you for your help.