diff --git a/ApplicationLibCode/ReservoirDataModel/RigCellFaceGeometryTools.cpp b/ApplicationLibCode/ReservoirDataModel/RigCellFaceGeometryTools.cpp
index b91cd3ecc4..0e33d3bce5 100644
--- a/ApplicationLibCode/ReservoirDataModel/RigCellFaceGeometryTools.cpp
+++ b/ApplicationLibCode/ReservoirDataModel/RigCellFaceGeometryTools.cpp
@@ -304,8 +304,18 @@ void RigCellFaceGeometryTools::extractConnectionsForFace( const RigFault::FaultF
             }
         }
 
-        std::pair<unsigned, unsigned> candidate( static_cast<unsigned>( sourceReservoirCellIndex ),
-                                                 static_cast<unsigned>( candidateCellIndex ) );
+        // Test if this pair of cells already has a connection. Check both combinations of cell index ordering to avoid
+        // duplicate NNC geometry for the same pair of cells
+
+        auto candidate = std::make_pair( static_cast<unsigned>( sourceReservoirCellIndex ),
+                                         static_cast<unsigned>( candidateCellIndex ) );
+
+        if ( nativeCellPairs.count( candidate ) > 0 )
+        {
+            continue;
+        }
+
+        std::swap( candidate.first, candidate.second );
 
         if ( nativeCellPairs.count( candidate ) > 0 )
         {
diff --git a/ApplicationLibCode/ReservoirDataModel/RigFault.cpp b/ApplicationLibCode/ReservoirDataModel/RigFault.cpp
index 9df8d36d34..04b9cb6b78 100644
--- a/ApplicationLibCode/ReservoirDataModel/RigFault.cpp
+++ b/ApplicationLibCode/ReservoirDataModel/RigFault.cpp
@@ -203,3 +203,33 @@ void RigFault::accumulateFaultsPrCell( RigFaultsPrCellAccumulator* faultsPrCellA
                                       faultIdx );
     }
 }
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+RigFaultsPrCellAccumulator::RigFaultsPrCellAccumulator( size_t reservoirCellCount )
+{
+    std::array<int, 6> initVals = { NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT };
+    m_faultIdxForCellFace.resize( reservoirCellCount, initVals );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+int RigFaultsPrCellAccumulator::faultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face ) const
+{
+    // Ensure no crash after creating temporary LGRs
+    if ( reservoirCellIndex < m_faultIdxForCellFace.size() )
+    {
+        return m_faultIdxForCellFace[reservoirCellIndex][face];
+    }
+    return NO_FAULT;
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RigFaultsPrCellAccumulator::setFaultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face, int faultIdx )
+{
+    m_faultIdxForCellFace[reservoirCellIndex][face] = faultIdx;
+}
diff --git a/ApplicationLibCode/ReservoirDataModel/RigFault.h b/ApplicationLibCode/ReservoirDataModel/RigFault.h
index d498763129..a763a7bff9 100644
--- a/ApplicationLibCode/ReservoirDataModel/RigFault.h
+++ b/ApplicationLibCode/ReservoirDataModel/RigFault.h
@@ -46,26 +46,11 @@ public:
     };
 
 public:
-    explicit RigFaultsPrCellAccumulator( size_t reservoirCellCount )
-    {
-        std::array<int, 6> initVals = {NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT, NO_FAULT};
-        m_faultIdxForCellFace.resize( reservoirCellCount, initVals );
-    }
+    explicit RigFaultsPrCellAccumulator( size_t reservoirCellCount );
 
-    inline int faultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face ) const
-    {
-        // Ensure no crash after creating temporary LGRs
-        if ( reservoirCellIndex < m_faultIdxForCellFace.size() )
-        {
-            return m_faultIdxForCellFace[reservoirCellIndex][face];
-        }
-        return NO_FAULT;
-    }
+    int faultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face ) const;
 
-    inline void setFaultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face, int faultIdx )
-    {
-        m_faultIdxForCellFace[reservoirCellIndex][face] = faultIdx;
-    }
+    void setFaultIdx( size_t reservoirCellIndex, cvf::StructGridInterface::FaceType face, int faultIdx );
 
 private:
     std::vector<std::array<int, 6>> m_faultIdxForCellFace;
diff --git a/ApplicationLibCode/ReservoirDataModel/RigNncConnection.cpp b/ApplicationLibCode/ReservoirDataModel/RigNncConnection.cpp
index 65ba39f922..b608ac957f 100644
--- a/ApplicationLibCode/ReservoirDataModel/RigNncConnection.cpp
+++ b/ApplicationLibCode/ReservoirDataModel/RigNncConnection.cpp
@@ -45,10 +45,14 @@ RigConnection::RigConnection( unsigned                           c1GlobIdx,
     if ( c1GlobIdx >= c2GlobIdx )
     {
         // Ensure the smallest cell index is the first index
-        // TODO : The face type is related to cell 1, so face should be changed to opposite face
-        // This causes visual artifacts for some models, so this change will require more investigation
         m_c1GlobIdx = c2GlobIdx;
         m_c2GlobIdx = c1GlobIdx;
+
+        if ( c1Face != cvf::StructGridInterface::FaceType::NO_FACE )
+        {
+            // The face type is related to cell 1, so use opposite face
+            m_c1Face = cvf::StructGridInterface::oppositeFace( c1Face );
+        }
     }
 }
 
@@ -69,10 +73,14 @@ RigConnection::RigConnection( size_t                             c1GlobIdx,
     if ( c1GlobIdx >= c2GlobIdx )
     {
         // Ensure the smallest cell index is the first index
-        // TODO : The face type is related to cell 1, so face should be changed to opposite face
-        // This causes visual artifacts for some models, so this change will require more investigation
         m_c1GlobIdx = static_cast<unsigned>( c2GlobIdx );
         m_c2GlobIdx = static_cast<unsigned>( c1GlobIdx );
+
+        if ( c1Face != cvf::StructGridInterface::FaceType::NO_FACE )
+        {
+            // The face type is related to cell 1, so use opposite face
+            m_c1Face = cvf::StructGridInterface::oppositeFace( c1Face );
+        }
     }
 }
 
diff --git a/GrpcInterface/Python/rips/tests/test_nnc_properties.py b/GrpcInterface/Python/rips/tests/test_nnc_properties.py
index e55cd1a289..b5b2fa85d9 100644
--- a/GrpcInterface/Python/rips/tests/test_nnc_properties.py
+++ b/GrpcInterface/Python/rips/tests/test_nnc_properties.py
@@ -25,7 +25,7 @@ def test_10kSync(rips_instance, initialize_test):
     )
 
     nnc_connections = case.nnc_connections()
-    assert len(nnc_connections) == 3627
+    assert len(nnc_connections) == 3416
 
     connection = nnc_connections[0]
     assert connection.cell1.i == 33