Why does flatten bends fail?

I have a part inherited from a sister company that we are attempting to turn to sheetmetal so we can flatten and plasma cut. This is a very basic part and can easily be remodeled as sheetmetal so it can be flattened, Or I can convert to SM, reorder the extrusion below the sheet-metal icon, delete the extrusion and create a SM part from the sketch so this is more of a why can't SW do this type of question.

   When I convert to SM and attempt to insert bends I get the error that one or more bends can not be processed. How do I determine which bend, or why?

SolidworksSheet Metal