I did some test this morning... just to add more info about the problem!
well.. I try to understand a log message from Luxrender - "P" s must match "N" s - or something like this.
so I increase the fillet edge on the chamferbox from 3-> 10 ( from odd-> to equal) and no shading problem
- smooth was on, no log error.
then I try to re render the scene with 3 edge for the fillet... again shading issue was visible. I try to increase the fillet to a equal number 4... the export of the scene failed... 3ds max crashed. I try with 4 for more than 4 times.. every time max crashed. strange that it crashed with 4 and not with 10.
I will try with other numbers of edge for the fillet... odd and equal. edit: max crash strangely only with 4 edges for the fillet
but the problem is also persisting for complex imported obj in 3ds max. I don't know if tessellating the geometry could help... but this solution will securely increase rendering time and have not much sense.