Cosmetic
Where the binding joins the neck you probably had a finish crack you didn't notice
Hand moisture has caused a buildup there
You my be able to clean it with a toothbrush
And fill it with nailpolish
Let some others chime in on the nail polish before you actually do that
I’ve got something similar going on with my Studio. The clear coat separated from the wood and semi chipped off.
One of these days I’ll get it fixed professionally.
I wouldn't worry about it till/if it becomes worse. It's probably no big deal. Based on how yellow your clear coat is, it looks like you might leave your guitar out of its case, getting some UV exposure (i.e. sunlight). My Les Paul is 15 years old, and it has nowhere near the yellow tint that your clear coat has. That can also contribute to cracks and shrinkage of the plastic, as well as discoloration. It looks to me like the binding has come a bit loose, perhaps due to shrinkage and hardening.
