DF Legacy - conflict between DEM and buildings

Dear Ladybug team,
I have a question concerning the modelling of Envimet terrain in DF legacy.
I have modelled a group of brep, merged together with a boolean union and linked to the DF Envimet Terrain component. When there is only the terrain in the file, everything works fine. However, if I add some buildings to the Envimet objects, when opening the resulting INX file in Envimet Spaces, 2d view seems fine, but in the 3d view the buildings disappear and they are not considered in the simulation, like they were not there! I tried to model the terrain differently, as a mesh, a closed or open surface, but the issue persists.

This is an image of the rhino model (the terrain is green, the buildings gray):

This is the Envimet Spaces 2d view, which seems fine (DEM height is correct):

This is the Envimet Spaces 3d view, without buildings (DEM is still there):
DEM03

This is the .gh file, if needed:
TEST_DEM.gh (64.5 KB)

thank you all
letizia