I would route it out and polish the edge. I believe what I see is the edge of the metal at the crack does not appear to be deburred, it may be but in this and similar locations you need to literally round the edges and polish the sheet edge to a smooth shine. All traces of the factory cut edge roughness should be removed. That is what I did and my bend was just as tight without a crack. I work aircraft structures, sheet metal at a major airline, have lots of experience doing this, proper deburring and polishing edges is required to get tight bends without cracking.
Greg