TV is flashing on/off every half second, consistently. This is not a typical dropped few frames or stuttering.
Xfinity Cable box and service (Motorola)
Sony 42" HDTV
Connected directly from HDMI out on the Xfinity box to the HDMI in on the Xbox.
Only the input TV stream is flashing. It flashes even when the TV app is constrained. No flashing in OnGuide or any menus, etc
No other app is having this problem.
Box has been fully reset (unplugged and rebooted).