Hi Shazbot, ok yeah I see doing just those ones are not working properly - really you haven't done anything wrong there that's some kind of bug in the fillet handling.

It may be possible to get it to work by having a bit more precise geometry though, that bottom face that looks planar is not actually made from a plane but rather some kind of sweep and it's got a slight angle to it. It generally helps when things that look like they're pretty much flat are made from precise planes rather than just swept or lofted geometry that is sort of close to being flat.

- Michael