A possible bug was found in the low energy neutron transport routines (neutron_hp). In the Method G4NeutronHPCaptureData::GetCrossSection, G4PhysicsVector::GetValue is called with neutron momentum (in GeV), where it seems that kinetic energy in MeV is applicable there. The same calls can also be found in G4NeutronHPFissionData and G4NeutronHPInelasticData.
solved in the had-01 tag; included in gean4 2.0