Error in GeoModelG4 when handling Ether and HyperUranium

When running fullsimlight on new geometry dumps (recently created), the simulation is aborted with the following message:

--- Warning from G4Material::G4Material() define a material with density=0 is not allowed.
 The material special::Ether will be constructed with the default minimal density: 1e-25g/cm3

-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : mat012
      issued by : G4Element::G4Element()
Fail to create G4Element Ether with Z= 500  N= 1   N < Z is not allowed

*** Fatal Exception *** core dump ***
 **** Track information is not available at this moment
 **** Step information is not available at this moment

-------- EEEE -------- G4Exception-END --------- EEEE -------


*** G4Exception: Aborting execution ***