I have a jazz bass that on the G string at the 12th frett the harmonics are correct. But if you try harmonics at any other frett it's dead and thuddish.harmonics are good on other strings.
probably a twisted string. Try loosening it and straightening it out. Could also be a dud string regardless
Sounds like a twisted string. Loosen the string until you can pop the coiled end off the tuner post. Chances are, it'll kinda "jump" in your fingers as it untwists. Pop the coiled string back onto the post - DO NOT WIND IT ON - and tune it back up. That should take care of it.