During Black Friday week I bought a Chromecast with Google TV.
I used it to replace my Chromecast 2nd generation.
The new one is in the same HDMI port as the previous one. The TV is a 10 year old Samsung.
Since the upgrade my TV sometimes switches from my TV decoder (on HDMI1) to the Chromecast (on HDMI2). This has never happened with the old Chromecast during the 5+years I used it.
The Chromecast GTV is on 24/7.
Does anybody know what causes my TV set to switch to a different HDMI input?
Try looking at your CEC/Remote settings. It seems like Chromecast is using CEC to force the input change when it wakes up. Play around with settings and see what works