ghost array caching problem assert shows potential problem
True in 8.1.0 - There's an assert in vtkDataSet::GetCellGhostArray() that checks that the cached ghost array - if there is one - matches the array in the CellData - if there is one. But vtkPolyData::RemoveGhostCells removes the ghost array from CellData without clearing the cached array and resetting CellGhostArrayCached. So later if vtkDataSet::GetCellGhostArray() is called it thinks it still has a cached reference to the array, but the pointer it checks against from CellData is NULL, and the assert fails.