Before I dive into this issue next week, can you help me out? This line of code in vtkPolyData::ComputeCellBounds() controls whether the bounds is computed in serial or threaded:
if ((numCells = cellA[ca]->GetNumberOfCells()) > 250000)
Can you change and then recompile the value of the number of cells to be something greater than the number of cells in your dataset? (i.e., force the ComputeCellBounds() to run in serial). This will confirm that the issue is related to threading…