It looks like the film inside this thermpane window is deteriorating. Do I have this correct? This doesn’t look like a broken seal. Or is this the same thing - does a broken seal cause deterioration of the film?
I assumed the white markings on the glass had something to do with the film. Are you saying this is something else?
Difficult to tell for sure because of the screen, but looks like film. A failed Low-E film will typically show some color tint (purple or green) in the metallic film around the deteriorated area. Of course a failed seal can cause the Low-E film to deteriorate too.
Whether it’s a Low-E film failure or failed seal is not all that critical. The effect (decreased thermal performance and reduced aesthetics) are the same as is the cure (replacement of the pane). It’s like trying to differentiate between an impact chip and a crack (it doesn’t really matter at the end of the day).
Looks like the low-e , Hard to tell in the pic but I’ve seen dozens of times where the glass was installed backwards. But like Chuck said , its defective either way.