Remove internal feature edges in mixed grid

Hi all,

I generated a mixed grid using gmsh consisting in hexa and tetra cells. However, some unwanted feature edges are present inside my domain. I tried to remove them following the procedure described in Feature External Edges Only: CleanToGrid then ExtractSurface but it does not work for me.

Here is my domain and the feature edges:

As seen in the left picture, the domain is divided into hex and hex split into tet (in green) in some regions for the purpose of remeshing them later. In the right figure, you see the unwanted feature edges (internal edges).

The mesh is accessible here: FileSender (too big for direct attachment in the forum)

I am using Paraview 5.12.
May you help me with this?
Thanks a lot

Your file contains some cells that are inverted which causes the issue you see:

You need to figure out why such cells exists in your data.