Flickerstrike doesnt work Unarmed ?

i tried making an "unincumberd" build wich counts me as Dual wielding... i asumed well flickerstrike would work wich it didnt

i asumed ok i guess thats a but weird but then i saw that Frenzy of onslaught works and it has the same conditions ???


if anyone has a clue why id love to know it bc im pretty stumped not to be able to play my build with Flickerstrike and have to resort to onslaught now