I have a part made in sheet metal. See attached. I can flatten and unflatten all day long in the part and there are no problems. As soon as I drop it into a drawing in the flattened state, the drawing views with the flattened part turn red and it says it has features that can not be unbent.
Again, I CAN unbend it when I have the part open and it flattens out just fine. This is only happening once it's in the drawing.
I'm on SW 2011 SP5.0