Hi pafurijaz, thanks for posting the file.

The geometry of the trim curves for the inner hole on this model is of very poor quality.

I tested some in Rhino and what initially appears to be an inner trim boundary made up of 5 edges is actually one long edge (and one tiny micro edge) that has an extremely tight awkward bend in it at what should be sharp corners:







There are also oscillations around those pseudo-corner spots:



I'm not sure exactly what is going on but I think it's probably so close to being non-G1-continuous that it's causing some problems in MoI in some of the algorithms that involve stepping along curves.

But the edge geometry here is of such very low quality that I doubt that it will be able to be fixed up automatically.

- Michael