Hi Dan yes if you could please post the file that would help. It looks like MoI is having difficulty trimming the fillets against each other though - it may help if you were to include the other neighboring edges in the fillet as well. That would allow the filleter to make a corner juncture patch instead of trying to intersect fillets of different sizes with each other which is an area that can tend to be buggy in the geometry library that MoI uses for fillet calculations.

- Michael