vtkMapper continuously modified when using named color arrays
When vtkGeometryRepresentation is using named color arrays in vtkGeometryRepresentation::UpdateColoringParameters, there is a call to vtkMapper::ColorByArrayComponent from vtkMapper::SelectColorArray which sets ArrayComponent to a value of -1. This value is then typically reset to 0 later on in vtkMapper::MapScalars (https://gitlab.kitware.com/vtk/vtk/-/blob/d87854341f81428acd7fbbd48746f0593dfde5ef/Rendering/Core/vtkMapper.cxx#L442).
At a next Render() of the scene, the aforementioned change of the ArrayComponent to 0 prevents vtkMapper::ColorByArrayComponent to early-out, updating the MTime and setting the ArrayComponent to -1 again, repeating indefinitely. This prevents detection of mapper content changes for geometries with named color arrays.
This seems easily fixed by changing the -1 default values to 0, or the 0 to -1.