Aha. TBH I am not a big bean grower because we have too many seasons that turn out 'not a bean year'. Beans simply hate it cold and wet, and now more than ever we can't guess when that might rule a summer month. But of those that I have grown, my favorite by far was the Pencil Pod Black Wax Bean. Yellow pod, black seeds. We had zero problem with any discoloration from the black seeds, if there was such a thing?... and they were tender and delicious and relatively productive and resistant to the ills of beans.
That is an old variety that remained popular, so IMO it's unlikely to be an issue. If anything it's a plus because the cut beans have the surprise color to show. And we do love surprises.

Also forgot to mention, it's very exciting to hear about disease resistance in beans.
As with tomatoes, there's a limit to how much time and space you can lavish on something that wants to turn into a pile of grey slime.
I would even consider to grow beans with the (disease resistant selected) tomatoes in the greenhouse, if I didn't expect them to contribute to a foul brood of the same.