I've had this issue with all four of my NUCs (NUC6CAYH) since version 9.0.0. It's still happening on 9.2.2. However, I'm running the default (Estuary) skin.
In all cases I'm using just a single HDMI display, but I have 4K, 1080p, and 720p devices. It happens on all of them which requires a reboot each time. 