Ever since I've had my Chromecast with google TV the internet fluctuates constantly in and out. I mainly experience this with the Spotify app more than anything else.
I spoke to customer support who had no solution for me, just wandering if anyone has or had the same problem as me :)
Set the CCwGTV to a static IP address, and not DHCP. I had that issue and setting the IP address in the Chromecast was what made it stop.
I have been having this issue, keeps coming up with connection lost. Can't really find out why, but I was using a third party USB C cable that had less pins, so have reverted back to original cable and restarted the router and I haven't seen it do it since, so fingers crossed.
Do you mean the internet connection on the device or in your home? I can certainly attest to some weird behaviors I've experienced on my CCWGT, yesterday I had to reboot my router just to get it to play youtube without buffering weirdly. Perhaps it's my router, but this is the only device which was having issues at the time and this isn't the only issue.