I’ve been working with VTK UnstructuredGrid files that contain time series. In your external test files I found cube-with-time.vtu which is essentially doing the same thing. Similar to how its described here Field Data as Time Meta-Data in VTK XML File Formats - VTK documentation .
In VTK 9.6 my datasets no longer load any data beyond time step 0. Instead a warning is emitted after reader.Update()
```
from vtkmodules.vtkIOXML import vtkXMLUnstructuredGridReader
reader.SetFileName(“cube-with-time.vtu”)
reader.Update()
2026-05-12 10:23:50.391 ( 32.958s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.435 ( 33.002s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.435 ( 33.003s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.435 ( 33.003s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.435 ( 33.003s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.435 ( 33.003s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
2026-05-12 10:23:50.436 ( 33.003s) [ D32FF9232C606AC] vtkXMLDataReader.cxx:286 WARN| vtkXMLUnstructuredGridReader (000002314CDB45C0): Another point data array named example data already exists. Ignoring.
```
On 9.5 this was working perfectly fine and the dataset was accessible for every time step.
On the same note ParaView 6.0.1 can read in cube-with-time.vtu, but 6.1.0 fails with the above warnings. Is this a bug (regression)?
TestReadXMLUnstructuredGridWithTime.py also triggers that warning if I run it locally but the assertion still succeeds as the GetNumberOfTimeSteps still seems to propagate.