The problem of dye rubbing off leather products is not new or unusual, and not all solutions work for all types of leather and dye, or work at all in some cases.
It would be helpful to know the type of leather, and the type of dye used, but I doubt that even Diamond knows that, as they likely buy these pockets from some international mass-producer.
Is it smooth leather or a suede-like surface? If smooth, I would try buffing it quite aggressively with a neutral shoe polish, like Kiwi. Not a lot of polish, and use cotton, or a lambswool buffer. A power buffer would be most effective.
If it's a suede-like surface I don't know what I'd do; maybe make liners for the contact areas from a material I know would not transfer dye.
