@AdamC and others, thank you for the detailed replies. Up to this point, I can check most of those off the list.
Oddly enough, I wore this jacket while in Yellowstone NP this past weekend and perhaps some of the steam coming off the geysers reacted with the sleeve? I mean, it's not like I was standing that close to them but that's all I can come up with. It has never been around bleach or been through the washer.
It is still one of my favorite IH jackets of all time and I love the olive color, hopefully the rest of it doesn't start discoloring. Less than ideal in my opinion.