I have got a 49XD8099 and recently updated (via USB) to the latest Android 6.0.1 version, v6.1004 (March 15 2017 release). I don't know if it has to do with the fact that after updating I could find out why I couldn't connect to the WiFi, and configured the tv to use WiFi accordingly, but since then I keep having the tv restarting Android randomly once or twice per day with the television in stand-by.

I first could notice it because after a reboot it goes to the HDMI 4 (since I don't have an antenna I have set it up that way to avoid turning on the PS4), and then checking with the side-loaded CPU-Z I can see the uptime. Now it just restarted in front of my eyes.

Again, the only difference is that I am now using WiFi. I'll try going back to wired and see if it happens again, still I am getting quite tired of this kind of issues. Anyone else getting the same problem?