I agree with 811952 - the c-clamp treatment works. This problem is endemic to Fenders, Fender copies, MM's, etc. (and is one of the reasons I bought my Alembic SJ). The physics behind the clamp idea is simple - it just prevents the axe, by inertia, from resonating, as it would otherwise tend to do, at a frequency close to but not exactly at the frequency of the note in question (note - note a problem if you fret the same note at the 12th fret of the D string) and thereby muting the note. More mass. If the clamp alone doesn't work, then weights clamped to the headstock will.