I had this happen on my P/J a couple times, what fixed it was to relax the string, letting it unwind by detuning it till it was loose, you may notice the ball end spin a bit, then re-tune the string. If this doesn't fix it, you may have a bad string, replace it. This is of course assuming the setup, nut slot, etc. is correct....best of luck!
Thanks, I will give this a try. It wasn't making this buzzy sound when I first put these on awhile back. Just noticed it recently.

