Finish lifting around frets

[holty]

Looking for some advice on the following. I've noticed that the finish on the neck of my '92 330 looks to be lifting around the frets. The finish looks pretty thick on the lower frets where the lifting is worse. You can't feel it and it doesn't seemed to have come through to the surface. I'm pretty sure it's the original finish. The guitar is in great shape and there isn't any obvious reason this has happend. Is this just part of the normal ageing of the guitar, or should I doing something! Advice welcomed.