Seasone highest grade not recording

Ok so i got a S+ with Thresh and i expected to get a chest coz i had 1 to win and i hadnt got with thresh but after the game i didnt get it and when i see collection it didnt record the same hapend with Lux , Nasus , Yi and even with the new cham Xayah i got S and didnt recive anything when i open collection and se Xayah it sais seasone highest grade:N/A so i was wondering is this a bug or am i wrong with something (ps : in profile i have 1 chest to win so no its not coz i havent got chests ) ty in advance