Thank you Orophin!
You just answered my question!
I guess it make some sense to prevent high level player to take low level mobs from weaker player.
I was trying to leveling my conjurer, so I didn't used my GLA for a while. I wasn't able to find any clues about it on lodestone and I just assume the issue was a bug, because I just notice it after the latest patch came out.
Thank you again!