Deep copy of polydata seems broken

Hi everyone,

in out project we recently upgraded from VTK 8 to 9. Following this I discovered an issue with copying polydata at this location in my code: MITK-Diffusion/mitkFiberBundle.cpp at master · MIC-DKFZ/MITK-Diffusion · GitHub

I am doing the following:


before the deep copy, poldata-source->GetNumberOfLines() is > 0, after the deep copy it is 0. So the copy seems to change the source. Using CopyStructure seems to be a workaround, but I would be happy to know if I am doing something wrong or if this is indeed a bug.