This road is actually controlled by China. According to de facto and the On the Ground principle, this road should be tagged its name Chinese in its name tag and " China" in its is_in: country tag.
note:en:2
Now the DWG doesn't allow users to change the boundary to show the fact situation, so you may this road is in Bhutan boundary on OSM, but do not change the tag mentioned. See https: //www.openstreetmap.org/changeset/111486876 .
note:en:3
Don't use too old data at the bottom to modify the road, thank you .