Low-E coating gone bad?

Half of the sliding door had this “condition”. At first, I thought it was a broken thermal seal, but under closer investigation, it looked more “metallic”. Is this a Low-E coating that has gone bad somehow? Thanks guys.

I would still say it is a broken seal.

When Windows turn white between glazing the glass becomes etched and cannot be repaired. It will do the same thing to the coatings.