Giant lifestone

Hello i use giant lifestone (cost 50 elcyum) and i get active giant sleep,active giant sleep sleep the target for 5 secont and reuse is 5mins with eva runes(dont know if this count in giants skills) this is normal?need fix it or change?I w8 one some answers from players(about they oppinion) and maybe from gms..... if they still watch the forum.