Really? Well, my experience with this aftertaste isn't recent, but waaaaaay back, with my grandfather's old carbon steel knives. I don't have the foggiest idea about who made them (from Solingen?), but I remember the distinctive taste I could feel if they were used when cutting meat on your plate. A childhood memory, but something that has stuck with me since.Sounds like the local carbon steel didn't use relatively pure iron, if it's leaving an after taste.
I don't have any experience with the current custom-made carbon steels. All the local custom blades that I have are stainless (but not hard stainless - like 420 or 440C).
Ha, if that only applied to knives...You really are boxed in, if you aren't rich.