Mobs go Invuln after moving

[Kers]

While in LOIO as a lvl1 necromancer, to the left side of Cabilis zone in. If i tag a mob with a spell, causing it to move from it's original point i attacked it at, it will turn invulnerable. If i run to a mob and swing at it/hit it, then run back to where it's safe to kill, the mob goes invulnerable.

Mob can still hit me, guards can still hit mobs, i just cant do any dmg. I won't show my melee attacks in my combat chat, and when i cast Lifetap, it shows that it does damage, but the mob's hp does not correlate that dmg.