[gameplay bug] Ionian Boots of Lucidity give no CDR on Rengar?

First of all i had this on the new gamemode black market brawlers which i was in and i bought Ionian Boots of Lucidity but noticed later that when i had rank 2 ulti that it didn't give me the cdr and i don't know why this happend. that's why i'm reporting it now. Then i tried in a custom game with riven and it did work so i was thinking if it only happend with rengar and tested it again. and it worked i got the cdr in the custom game but in the normal game not? i also tried in aram with fiddle and i also got the cdr . But it i'rn sure i didn't get it in the game . But maybe it was a one time thing? hope you guys can fix it.

EDIT : http://matchhistory.euw.leagueoflegends.com/en/#match-details/EUW1/2231241852/30154626?tab=builds Game details.