GBitmap saved to disk as a MSBMP distorts color

I have a gBitmap, (Created via TSShapeInstance::snapshot,) that looks perfect when I save it to disk as a PNG via GBitmap::writePNG. When I save it to disk via GBitmap::writeMSBmp, however, the resulting bitmap shows serious color distortion, in a red/green direction. (I.e. skin tones look green, and so on.) Anyone have any guesses as to why, or what may be happening here? The color mode of the GBitmap is GBitmap::RGB.