Hi David,
I’ve seen a gradual deterioration of my ‘red’ lines with an Atik 414ex on an Alpy, and am close to investigating the problem to see whether it’s simple tuning or something more sinister as yours.
Were you able to see the film yourself on the surface of the cover glass using a magnifier after it had been pointed out to you – or had Terry already cleaned it? I’m wondering how ‘difficult’ it is to pick up.
Paul