I have one of the cool "Limited Edition" FSR MIJ '66 Jazz re-issues. Love the bass! Recently, however, I notice that if my thumb ever comes in contact with the pole pieces on the neck pickup under the E string, there is quite a bit of hum/buzz. There is much less hum, however, if I touch any of the other pole pieces on that pickup. The bridge pickup is totally fine. Any ideas what might be going on here?