diff --git a/ApplicationCode/GeoMech/GeoMechDataModel/RigFemPartResultsCollection.cpp b/ApplicationCode/GeoMech/GeoMechDataModel/RigFemPartResultsCollection.cpp
index 4b6a7bde69..0c90b2c678 100644
--- a/ApplicationCode/GeoMech/GeoMechDataModel/RigFemPartResultsCollection.cpp
+++ b/ApplicationCode/GeoMech/GeoMechDataModel/RigFemPartResultsCollection.cpp
@@ -667,7 +667,15 @@ RigFemScalarResultFrames* RigFemPartResultsCollection::calculateDerivedResult(in
             for(int elmNodIdx = 0; elmNodIdx < elmNodeCount; ++elmNodIdx)
             {
                 size_t elmNodResIdx = femPart->elementNodeResultIdx(elmIdx, elmNodIdx);
-                dstFrameData[elmNodResIdx] = formNameIdx;
+
+                if (formNameIdx != -1)
+                {
+                    dstFrameData[elmNodResIdx] = formNameIdx;
+                }
+                else
+                {
+                    dstFrameData[elmNodResIdx] = HUGE_VAL;
+                }
             }
         }
 
diff --git a/ApplicationCode/ReservoirDataModel/RigCaseData.cpp b/ApplicationCode/ReservoirDataModel/RigCaseData.cpp
index d7e12650df..b9749dbd51 100644
--- a/ApplicationCode/ReservoirDataModel/RigCaseData.cpp
+++ b/ApplicationCode/ReservoirDataModel/RigCaseData.cpp
@@ -492,8 +492,14 @@ void RigCaseData::setActiveFormationNames(RigFormationNames* activeFormationName
         if(!m_mainGrid->ijkFromCellIndex(cIdx, &i, &j, &k)) continue;
 
         int formNameIdx = activeFormationNames->formationIndexFromKLayerIdx(k);
-
-        fnData[cIdx] = formNameIdx;
+        if (formNameIdx != -1)
+        {
+            fnData[cIdx] = formNameIdx;
+        }
+        else
+        {
+            fnData[cIdx] = HUGE_VAL;
+        }
     }
 
     for (size_t cIdx = localCellCount; cIdx < totalGlobCellCount; ++cIdx)
@@ -505,8 +511,14 @@ void RigCaseData::setActiveFormationNames(RigFormationNames* activeFormationName
         if(!m_mainGrid->ijkFromCellIndex(mgrdCellIdx, &i, &j, &k)) continue;
 
         int formNameIdx = activeFormationNames->formationIndexFromKLayerIdx(k);
-
-        fnData[cIdx] = formNameIdx;
+        if (formNameIdx != -1)
+        {
+            fnData[cIdx] = formNameIdx;
+        }
+        else
+        {
+            fnData[cIdx] = HUGE_VAL;
+        }
     }
 
 }