The TSB states: "Heat from the daytime running light (DRL) LEDs may damage the DRL lens. If the lens is damaged, it may appear that
some of the DRL LEDs are not working."
The most common issue I see is failure of the LED's - not failure of the lenses.
I believe they are one in the same, really. I think what they are referring to as "the lens" is the plastic rod with prism optics that's used to spread the light output from the 2 LED's in the center of the DRL to the inner corner of the headlamp (the outer corner of the DRL has its own, single LED that isn't as prone to failure). The heat from the inner LED's in their 12V mode is great enough to melt the plastic rod and as a result, the melted plastic then "smothers" the LED's and causes them to fail from overheating.
I can see how the rod melting could cause the light to no longer pass through it, making it look as if the inner portion of the DRL is completely out. However, if the LED's were still functioning in that case there should be a massive bright spot in the middle of the DRL where those two LED's sit. My theory is that condition may exist briefly, but the LED's usually die before the owner notices that "the lens" has failed. I say that because the inner LED's have been completely dead on every headlamp I've seen with DRL failure.
Regardless, the solution to both scenarios is the same: replacement of the affected headlamps.
As for VIN # eligibility, I'm really hoping that they did that to exclude the LX models from the TSB (as they don't have the LED DRLs) and that there aren't any cars with the LED DRLs being excluded from this extended warranty. From what I've seen, they're all affected regardless of year (16 or 17), body style, or trim level.