http://www.ign.com/articles/2017/05/25/samsung-tvs-to-fix-nintendo-switch-hdmi-problem
I know quite a few users here have been having this issue based on comments. (I also have a less serious issue with our LG TV randomly pulling up a pop-up).
An issue on Samsung TVs that saw them automatically switching HDMI channel to a Nintendo Switch console in sleep mode should be fixed soon.
Samsung's latest TVs include a feature that has them automatically switch to what they perceive to be a newly-active HDMI input, but docked Switch consoles (among other devices) appear to trigger that feature even when notionally turned off.
Speaking to The Verge (via Polygon), a spokesperson said: "Samsung has been following the comments on our Community Thread and we will be issuing a Firmware update early this summer that will address this behavior and provide the level of convenience that was intended."
I know quite a few users here have been having this issue based on comments. (I also have a less serious issue with our LG TV randomly pulling up a pop-up).