Shading error after flipping normals on mesh

As far as I can guess is that in the initial state of the object, the vertex normals are as they come from the DCC, but after the modeling operation they get recalculated somehow that doesn't match the original.

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1 - Import attached file

2 - In the modeling tools select all faces and flip normals twice

3 - Inspect the shading. For this you can create a copy of the object before step 2 to compare.

Result: Shading error on some parts of the object

Expected result: Shading should be the same as before modeling