--- Common/DataModel/vtkPolyData.cxx    2021-07-31 23:02:31.905458045 +1200
+++ Common/DataModel/vtkPolyData.cxx.new    2021-07-31 23:30:03.545281471 +1200
@@ -12,6 +12,7 @@
      PURPOSE.  See the above copyright notice for more information.

 =========================================================================*/
+#include <iostream>
 #include "vtkPolyData.h"

 #include "vtkBoundingBox.h"
@@ -523,7 +524,7 @@
     // thread pool).
     for (auto ca = 0; ca < 4; ca++)
     {
-      if ((numCells = cellA[ca]->GetNumberOfCells()) > 250000)
+      if ((numCells = cellA[ca]->GetNumberOfCells()) > 250000000)
       {
         // Lambda to threaded compute bounds
         vtkSMPTools::For(0, numCells, [&](vtkIdType cellId, vtkIdType endCellId) {
@@ -542,6 +543,7 @@
       }
       else if (numCells > 0) // serial
       {
+        std::cout << "Processing Serially" << std::endl;
         vtkIdType npts, ptIdx;
         const vtkIdType* pts;
         for (auto cellId = 0; cellId < numCells; ++cellId)