[mpfa][localassembler] detect zero transmissibilities also in outside scvs

dumux/discretization/cellcentered/mpfa/omethod/localassembler.hh

@@ -250,11 +250,13 @@ private:
                     {
                         if (abs(wijk[faceIdx][0][localDir]) < wijZeroThresh)
                         {
-                            insideZeroWij = !curGlobalScvf.boundary();
                             if (!curIsDirichlet)
+                            {
+                                insideZeroWij = true;
                                 faceMarkers.emplace_back( std::make_pair(curLocalDofIdx, faceIdx) );
                             }
                         }
+                    }
 
                     // if we are not on a Dirichlet face, add entries associated with unknown face pressures
                     // i.e. in matrix C and maybe A (if current face is not a Dirichlet face)
@@ -308,7 +310,8 @@ private:
                             const auto& otherLocalScvf = iv.localScvf(otherLocalScvfIdx);
                             const auto otherLocalDofIdx = otherLocalScvf.localDofIndex();
 
-                            if (otherLocalDofIdx == curLocalDofIdx && insideZeroWij)
+                            // check for zero transmissibilities (skip if inside has been zero already)
+                            if (otherLocalDofIdx == curLocalDofIdx && !insideZeroWij)
                                 if (abs(wijk[faceIdx][idxOnScvf][localDir]) < wijZeroThresh)
                                     faceMarkers.emplace_back( std::make_pair(curLocalDofIdx, faceIdx) );