i configured the admin server claim like i wanted (players able to interact with npc / using buttons / trapdoors / doors / mod blocks /etc)

and i noticed that when i'm /op all those rules don't apply anymore, the other players lose the perms to interact with what i configured in the first place only when i'm opped for some reason (i'm on 1.21.1 fabric 0.16.14)

If it happens with no message in chat, then it's not caused by OPAC. It's vanilla spawn protection that enables when there's at least 1 opped player.