I blame both companies for this issue :/

First off, Samsungs TV's which were released in 2016 whereas the KS8000 (KS8090 EU version) is a part of has a certain feature installed which auto switches the HDMI source to the device which was powered on. You cannot disable this feature!!! So, each time you are watching TV and for instance, turn on the PC, the TV will jump to the Source of the HDMI of the PC even if there is no picture being sent to. This issue got even worth by using the Nintendo Switch in the docking station.

I don't know why, but the Nintendo switch randomly wakes up the HDMI port when it is in standby. So when I am watching TV and the Switch is in the dock, the TV randomly changes to the HDMI port of the Nintendo Switch. This is really annoying. And I am not alone on this:

https://en-americas-support.nintendo.com/app/social/questions/detail/qid/48818/~/sleeping-switch-auto-switches-hdmi-input-on-samsung-smarttv/session/L3F2LzEvdGltZS8xNDkxNTYyMzUyL3NpZC9mVVQxaFRFS01GTjVJakg5JTdFWDZDczV3REZzNW0wQXhkU2kzeHFJb3QlN0VqelRwUVg1MEhrcmlvcVNuN2RCeU56UEwlN0VyanhJRDhIS0k5R1ZUJTdFdldGRHlJd2lfUDhkZFM2Q1gyaXhYMU1MTTJ4NkdleVJnc1ZyU1NFZyUyMSUyMQ==/comment/8736

I've already contacted the Samsung TV support and they are aware of this issue because of many complaints from customers. So they offer an unofficial firmware for the customers who are complaining about this issue. I've got it, too. But sadly, the issue is still present. I've yet to contact the support again, but don't have that much time to do so recently.

I've also recently contacted the Nintendo support on this issue to see if they are even aware of it. Will post an answer as soon as I will get one.

So, does anyone else have the same issues as I do? Got any solutions?

More reports:

@SamsungSupport y'all have a major problem. It's becoming bigger with new @NintendoAmerica #SWITCH being hooked up. https://t.co/3H0m2yjwCZ

— Chris Hamby (@Chris_Hamby) March 4, 2017

https://www.reddit.com/r/NintendoSwitch/comments/60e9cz/switch_causing_hdmi_input_on_many_newer_tvs_to/

Update:

https://mynintendonews.com/2017/05/24/samsung-announces-tv-firmware-update-to-help-switch-owners/

Fixed: Nintendo Switch Firmware 3:0 

Improvements to prevent unintended HDMI input change with certain TVs while the console is docked in Sleep Mode 

Sounds awful.
That's why I hate automatic switching. It almost never works like it's supposed to.

Turn the setting off. Either on your TV (apparently you can't) or on your Switch. That's been a "feature" since the PS3 days and I've been turning it off, ever since.

Like I said. I can't. That's not possible. Samsung is forcing their customers to use this.

http://amp.imore.com/how-stop-your-nintendo-switch-taking-over-your-television

I have a Sony but I hope that works for you. My Bravia had that as the default setting but I was able to turn it off. To many devices (including my Switch) had the option!

That sounds like a shit TV lol xD

My house is all Sony TV. No problems like this.

I clicked the link in your op. Seems like my solution is no help. Maybe try a shitty cheap HDMI cable?

Nope. Sadly this still is not working. It automatically switches to the switch even if the switch is in standby. It still sends out randomely a signal to the TV for no reason.

On TV it's called Anynet+ (HDMI-CEC) and it is set to off. Yet, other devices can still change the HDMI port by booting up.

It's active on all Samsung 2016 TV's. They really fucked this one up.

Another link to the issue.

https://us.community.samsung.com/t5/TVs/Turn-off-auto-detect-HDMI/td-p/2578/page/13