Vintage Stingray hums

Hey there! I have an old Music Man Stingray (1976) and it sounds amazing, but it has a bit of what seems to be a 60 cycle hum. The pickups appears to act like a single coil, where the hum will lessen as I move my bass around. Is this normal? I know the pickup is wired in parallel, but I would think that it would still be humbucking. I guess I am not familiar enough with the electronics. Any info would be greatly appreciated!