After five purple pea seeds found in a single pod last year, I only had a single pod full of purple seeds. That pod was attacked by pea moth, I could only rescue a single seed. Plants were very true to type.
Preliminary conclusion is that the purple trait in this color variation in Golden Sweet probably depends on environmental factors.
I probably can’t resist sowing the last purple seeded Golden Sweet next spring, just to see what happens. I don’t expect to find any purple seeds in that future batch, but who can tell without trying it out themselves?