Hi Igone, this looks like a bug in the geometry library that MoI uses. It appears that some of the fillet surfaces of the center hub are not intersecting properly with the outer rim.

If you still have an earlier stage of this model, you may be able to get better results by applying the fillets to the hub after you do the boolean, instead of before doing it.

I have saved the model and I will submit it as a bug to the people who make the geometry library.

Thanks,

- Michael