I recently ran into a model that appeared the same. It "appears to be a simply constructed solid, the many of the fillets are naked. There doesnt appear to be anything like overlapping trim boundries or fincky edges or anything. I'm thinking this might be something related to "Tolerances" set in other apps that then dont propogate unless the same tolerance is known in the receiving app.

We've discussed this before Michael, with regard to Rhino and you described your thoughts that having that variable tolerance value was a design mistake that lead to these types of situations.

I've requested the file from Anis also to have a looksee at it.