Prevent reindexing between timesteps when using the ExtractSurface filter

Hello Support!

I am currently trying to compute a surface integral in paraview.

This is my current setup:

Source: .vtu
ExtractSelection: Extract cells around the surface of interest
ExtractSurface: Extract surfaces to make them selectable
ExtractSelection: To obtain only the surface I am interested in
IntegrateVariables: To compute a surface integral

Now, whenever I move to a new time step, the selected surface elements are assigned new IDs and thus have new orientation and values.

Is this expected behavior?
What is the intended way to compute a surface integral?

I would be happy for any help on this!