diff --git a/libsrc/meshing/smoothing3.cpp b/libsrc/meshing/smoothing3.cpp
index 039bbf64..4af0128a 100644
--- a/libsrc/meshing/smoothing3.cpp
+++ b/libsrc/meshing/smoothing3.cpp
@@ -335,6 +335,20 @@ namespace netgen
   {
     static Timer tim("PointFunction - build elementsonpoint table"); RegionTimer reg(tim);
 
+    Array<bool, PointIndex> non_tet_points(points.Size());
+    non_tet_points = false;
+    // Don't optimize if point is adjacent to a non-tet element
+    ParallelForRange(elements.Range(), [&] (auto myrange)
+        {
+          for(auto ei : myrange)
+            {
+              const auto & el = elements[ei];
+              if(el.NP()!=4)
+                for(auto pi : el.PNums())
+                  non_tet_points[pi] = true;
+            }
+       });
+
     elementsonpoint = ngcore::CreateSortedTable<ElementIndex, PointIndex>( elements.Range(),
                [&](auto & table, ElementIndex ei)
                {
@@ -344,6 +358,7 @@ namespace netgen
                    return;
 
                  for (PointIndex pi : el.PNums())
+                   if(!non_tet_points[pi])
                      table.Add (pi, ei);
                }, points.Size());
   }