Not a flaw, but a feature of lightweight nickel plated alloy.
Aka they get worn down. They are not good old steel like the normal mech.
Although the marketing says it is to reduce wear, I can only assume that's a play on 'wear' and means the alloy part isn't ripped apart on the first few rides, and not comparing it to the steel mechs ;-).
Hinged is 'differential plate design' , given all the mechs have hinges I suppose.
I think Shimano sorted the problem in the good old fashioned, by a replacement plate spare part.