Wifi 5ghz problem in my cromcast but cable fine
Hey @RumRush, I would recommend you to contact Stadia support to figure out if the chromecast is actually the cause of the problem. If so it also might be that it is defective, but just to be sure, the support can help you with additional troubleshooting steps regarding that problem, before you replace the chromecast.
It sounds to me like an HDMI-CEC/HDMI Handshake issue with your TV/CCU. When this problem occurs, try just changing the input away from the CCU to something else, then change the input back to your CCU and see if it clears up. If it does, then that's definitely what it is and I'm afraid there isn't much more you can do about it but hope that an update on either side of the equation fixes it eventually.