PVS-Studio warning V501 for VTK

void vtkTransformToGrid::UpdateShiftScale()
{
  int gridType = this->GridScalarType;
  if (gridType == VTK_DOUBLE || gridType == VTK_DOUBLE)
  ...
}

This suspicious code was found in VTK project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions to the left and to the right of the '||' operator: gridType == 11 || gridType == 11 vtkHybrid vtktransformtogrid.cxx 184

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/