That’s not a function of the Port, the Port simply plays what it is sent. Is the port connected to a cable box?  If so, cable companies often reboot the box in the middle of the night and if your Port is connected directly to the box, the reboot will cause audio to come out of the cable box.

thank you.  I think that must be what the problem is!  Yes, it is hooked up to cable box and I need to remember to turn the cable off when I go to bed or go away!  You are just reconfirming what I dreaded.

You could turn off Autoplay on the Port, but then you have to manually select “TV” every time you want that.

If your TV has an optical port, get an inexpensive optical to analog converter and connect the TV to the port.