It sounds like the string is hitting a fret wire further up the neck. You may need to adjust the truss rod in the neck or raise the action a bit to cure it. Play the problem note and look closely as you play at the string to fret wire clearance at each fret of that string. You will probably see it hitting one or to frets up.

If you don't know how to adjust your truss rod don't attempt it. Just raise the Bridge or Trem just a little instead.

Hope that helps!