Assuming this is a production issue:
Those sorts of production errors (even for
SWed items) would probably not lower the value very much for most collectors.
However, Shrink Wrap fanatics (I think) are more fanatic about near perfection than many other collectors might be.
I suspect it would be more of a problem for them.
From my experience reading posts and other things, most
SW fans expect near perfection from
SWed items and even if it was a production error, it would likely detract from the items value significantly.
If the problem is color fading from exposure to sunlight... well that is a moderate hit on grading
IMO.
I have seen plenty of issues like that from older modules.
Especially the Monochrome TSR Modules and even more so for the Aussies...