Retayne is used to set dyes. You don't use it on a completed quilt, or on more than one color at the same time. I agree with Tartan that someone may have unknowingly slipped another pen into the signing, and that could be the one that bled. Or maybe there was a faulty Pigma pen. For the future, I wonder if there is a way to test the signed blocks before you put them in a quilt, perhaps by immersing them in water after you heat set them? Maybe you could experiment with that idea.