I see before the two extrusions makes you the flat model.
almost certainly it bothers him the tilted cuts and curves on the sheet thickness.(also to me it does it occasionally)
try by making a supestrusion instead of the "contour flange" giving the right rays in the sketch, cut this with as many surfaces that you get from the same sketches of the extrusions and then thicken to "spessore"
I think you're right. looking better at that extrusion, it cuts so not perpendicular to the sheet and also the bending rays.... probably that. Now I try as you say.
I finally managed. I worked with the surfaces, both for the sheet profile, and for the curves that intersect it and cut it. then I radiated the usant surface as a radius value "fold" or "thickness+fold" depending on the cases. then I have thickened his scissors and so it always works! in short if I can share a short video because I think it can be useful to other colleagues who work the sheet :-d