I've been printing with Forte papers for years. Print contamination by dirty fingers has plagued me with this paper. I've noticed it with the Poygrade V also. I wear surgical gloves now and the problem has disappeared. I wash my hands with the gloves on with hot water between each cycled print. I also give the prints a good rinse under the faucet after fixing (1 minute in Hypam), and then it goes into the water bath until I'm ready to tone. I also wash and dry my sqeegee and squeegee platform before each use. Residual toner and or developer on faucet levers, on the edge of the table, sink, etc can come back to haunt you. And yes, the contaminated areas have always been a lavender or purplish color.
No problems now.