Predator shoes definately messed up kayn buying items, it wouldnt let me get red or blue final jungle item forcing me to only buy cinderhulk. Next I bought components for deathdance and blackcleaver but wont let me buy it either.
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2639917744/36765548?tab=builds
I had this problem when playing Kayn with predator shoes as well, definitely not a one-off bug.
same here
same here ive eventually been able to buy the items after having to wait and buy other items though
http://matchhistory.oce.leagueoflegends.com/en/#match-details/OC1/191152299/200093824?tab=builds
i had to settle for buying merc treads then going onto duskblade and was finally able to buy my warrior at 18 minutes
Had the exact same problem .. I could only buy items at their full price even if I had components
