Oh snap I just reread. The PINK was shorter than the red..??
That blows my whole theory out of the water! lol
OOH actually, maybe not. Depending on HOW pink the pink is (as in, is it a diluted red dye, or a combination of red and white dyes) there might be heavier pigmentation. "titanium white" was what I used when I wanted to paint over a darker color and not have it bleed under, it was a real thick and viscous paint, so maybe that made less of the pink yarn soak up more dye to leave it at 50g?
I'm talking out of my butt here, really...