Failed test_co2_tpfa/test_co2_tpfani

rtest_co2_tpfa: /dune/modules/dune-alugrid/dune/alugrid/3d/entityseed.hh:78: static bool Dune::ALU3dGridEntitySeedBase<0, const Dune::ALU3dGrid<2, 2, Dune::hexa, Dune::ALUGridMPIComm> >::Bnd<0, ALUGrid::Gitter::hasFace>::isGhost(Dune::ALU3dGridEntitySeedBase::KeyType *) [codim = 0, GridImp = const Dune::ALU3dGrid<2, 2, Dune::hexa, Dune::ALUGridMPIComm>, cd = 0, Key = ALUGrid::Gitter::hasFace]: Assertion `key' failed.

with dune master + clang.