I don't know that it's intentional design, or simply variance among hangers. Most frame builders use stock hangers without modification. If i's a replaceable aluminum hanger, chalk it to design.
Variance in hanger stop tabs is one reason that many (most) modern derailleurs use a stop cam between the Rd and hanger, The cam will engage on just about any hanger, and puts the RD maker in control of B-screw engagement.
Try the foil pea and see of you like the results, then decide if you want to live with the pea (carry spares) or do something more permanent.
Changing RDs may not solve anything, unless you switch to one with a stop cam.
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