Achievement "Movin on up" didnet unlock

ok so i was playing halo waypoint using the codes to unlock exp for halo 4 this exp ranked me to rank sr20 but i didn’t get the achievement for ranking to sr 20
the achievement name is movin’ on up

i enter the codes in the classified section of halo waypoint this unlocked art armour and some exp for halo 4 i was level sr 19 before i did this it ranked me to sr 20 but i failed to get the achievement for doing so

any help regarding this issue would be greatly appreciated