Wolf Note?

I have built a steel string guitar that has an annoying high pitched pulsing overtone. The guitar is an x-braced OM style with a thicker depth (more in line with a dreadnaught depth). I have built several of these that do not have the annoying overtone, so I don't think its the specific shape that is causing it.

The overtone occurs when the note B2 is played on the G string, 4th fret. Interestingly, it does not occur when the open B string (same note) is played. There is a slight amount of the overtone 1/2 step up or down from the note (Bb or C), but it is most noticeable at B2, when played on the G string, 4th fret.

I have both an audio recording of the pulsing overtone and a visual recording of the spectral analysis which clearly shows the pulse at about 2800 Hz. This format will not allow uploading of these file types, but I can do that if there is another method.

Any ideas or suggestions about this would be welcome.