Well, that was not expected at all from Samsung. It seems Samsung is pushing the Grace UX we saw on Note 7 to Galaxy Note 5 sets in Korea, model no. SM-N920K to be specific. The update that installs the Grace UX on Note 5 is build N920KKKU2CPJ4.
If you own a Note 5 in Korea, or simply the one whose model no. is SM-N920K, then check for the update not under Settings > About device > System updates.
The PJ4 build is based on Android 6.0.1 Marshmallow, of course, and quite reasonably then, the Grace UX it comes packing it different from the Grace UX we’re seeing on Nougat beta update on Galaxy S7 and S7 Edge.
Check out the screenshots at the top and below, which comes from Galaxy Note 5 on build N920KKKU2CPJ4.
Also read: Samsung Galaxy Nougat update release