This is already fixed in development branch (available at https://github.com/LibRaw/LibRaw ) in two ways
1) Internal LibRaw color profile is copied to imgdata.color.cam_xyz[] ever for DNG files.
2) For DNG files full DNG color data preserved in imgdata.color.dng_color[2] (if DNG contains two color matrices, then both matrices are preserved)
This is already fixed in development branch (available at https://github.com/LibRaw/LibRaw ) in two ways
1) Internal LibRaw color profile is copied to imgdata.color.cam_xyz[] ever for DNG files.
2) For DNG files full DNG color data preserved in imgdata.color.dng_color[2] (if DNG contains two color matrices, then both matrices are preserved)