On some CNC software packages you can add a bubble or dog-bone fillet to geometry because obviously the cutting tool cannot cut a square inside corner. However having to wait until the CNC software to add these fillets means it is easier for these to get omitted due to miscommunication etc.
I would be great to be able to add these through the 2D or 3D fillet tool in Inventor itself so that you can export exactly what you want to cut out of Inventor.
Please see images for further explanation