Oke, here’s the evidence, that the magenta staining is an artifact introduced by Lowry. The magenta staining was always present, even in 1977 prints. The 2004 color grading made it more apparent, but if you look closely at the 4K77 frames you will notice it. It is made more apparent if you match the print to the bluray. The colors are identical, including the magenta staining, which must mean it was already there from the get go.
4K77:
Bluray:
4K77 matched to bluray:
