Xfinity Flex device (not remote) turns on TV when no one present

Hannspree TV with Amazon Fire stick on HDMI1 and Flex on HDMI2.

With TV input set to component (DVR - not HDMI), and TV off, the Flex device appears to be powering on the TV  overnight.  If I remove power from the Flex, this does not happen.  Never happens with Amazon Fire stick.

I'm guessing this is CEC (Consumer Electronics Control), but I don't see options on the Hannspree menus for CEC, nor with the Flex.

FWIW, I don't mind the Flex UI, but prefer using apps on Amazon Fire stick, rather than Flex, because the Flex remote stinks.