In that situation is it most likely that the fret is just eased out of the fingerboard a little? I have a (new to me) Precision that buzzes on the 9th, 10th and 11th frets of the G string (increasing buzz in that order) but is fine on the 12th which suggests the 12th fret is a little high, but this seems to affect the G string only, and I can't see that the fret is proud at all. Granted, I have a low action (1.7 or 1.8 mm at the 12th fret on the E string) which Dunlops (40 to 100) but that's the sort of action I like on a bass, just not with 11th fret buzz. The action is nice otherwise, with no other unwanted buzz. I certainly don't intend trying to dress the frets myself, though. I barely trust myself with soldering on a bass.