When contouring a 2D vtkImageData (*i.e.* extent is `1` in one dimension), at some point a `Scalars` array is expected in input instead of using the array returned by `GetInputArrayToProcess`. This occurs in [vtkSynchronizedTemplates2D](https://gitlab.kitware.com/vtk/vtk/-/blob/master/Filters/Core/vtkSynchronizedTemplates2D.cxx?ref_type=heads#L93) In the best case, this produces the correct output while printing the following error: ``` ERR| vtkImageData (0x556778761410): No Scalar Field has been specified - assuming 1 component! ``` But if `Scalars` is an array with a different number of component, this leads to a wrong output. ## Reproducer I have a ParaView statefile : [wrong_contour.pvsm](/uploads/289103b0abb226cb93fbe04f7474ba1f/wrong_contour.pvsm) This creates the following pipeline: * `FastUniformGrid, WholeExtent [0, 0, -10, 10, -10, 10]`: produces a 2D vtkImageData with some point data arrays * `ProgrammableFilter`: a python code to set a 3-components array as point data `Scalars` * `Contour`, on `DistanceSquared` (a 1 component point data array)