In one of my steel parts there are 4 bends. I have updated this part and as such have unfolded, then modified, and then folded the part again. Now when I click on flatten, it only shows the bend lines for 2 of the bends (was only showing one but I have since resolved one of the bend lines not showing). Whatever I try it won't show the bend lines. I have tried to modify the part so that the bends are not failing and can in fact bend - still didn't work.