hayder1983 I looked up their X80K review to find that, as usual, their claim is not true. You can see in their own test picture that there is obvious flicker on at least the lowest brightness levels. However, it is true that Sony in general has been known to care more than other TV manufacturers about at least trying to have a steady backlight.
It is much more complicated though. There are more situations where there could be introduced flicker, e.g. by simply switching channels or having a black picture in between loading screens or movie scenes, and rtings doesn't bother to test those.
Diamondintherough we have talked recently about how the TUV certificate is surprisingly worthless, as they certificate monitors that use PWM as "flicker-free".