When importing converted DNG files into Lightroom Classic they get automatically converted to B&W even though the import Profile is set to None and all Presets are set to defaults. This does NOT happen when converting the same files with DNG Converter v11.3. BTW the compatibility is set to 7.1 and later.
Incidentally I've experienced this with Fujifilm X-T30 raw images.
This phenomenon has been reported in the LightRoom forum in the past; since it isn't happening on v11.3, I consider this as a DNG Converter regression.