It says it will call upon all August Celestials to aid, which means I will get a much shorter FoF immediately after I cast it. That is the case for most of the times, but sometimes it just doesn’t happen.
Also there is no buff indicating the celestial is in effect, the only thing I can see is the visual where Yu’lon appears above your head. If I understand it right, as long as it can be seen, I get to channel FoF in half of the time. So the question above may be asked in another way: Not everytime Yu’lon will be present after I cast unity within, why?
Also how to understand this 200% effectiveness in the desciption? Does it mean I get to cast FoF in 1/4 of the time? certianly not. So can anyone explain how does this number apply to Yu’lon’s effect?