If TV Only power is not working in Flipper is is probably because either the STB does not turn off, or because the cable installer setup HDMI-CEC.
HDMI-CEC is a standard tat allows the TV to control the STB and vice versa. Brands can call it different things, like the links below.
So make sure that HDMI-CEC s turned off.
For more details, look in your TV Settings, manual, or use Google.