Sounds like CEC HDMI communication between the FTV and your TV. When you turn one device off, the device that receives the signal to turn off tells the other device to turn off or go into standby. Maybe there's a setting in the FTV to turn that feature off? Or, you could probably disable it at the TV. Samsung has a different name for it (AnyNet or some such).
XDA needs a "2nd Post Wiki" automatically generated in each thread. Such a thread wiki has proven effective on other sites to cut down on useless thread clutter and questions which have been answered repeatedly. The idea is simple. A community-editable wiki is inserted immediately beneath the OP to address current issues relating to the topic. Most OP/devs don't have the time to continually update their OP to address ongoing issues. Let's let the community do that for them!