It is how LOTRO has always worked. LOTRO is server authoritative. In other words, for the game, the server determines damage and updates the client at a specific time interval (server tic rate), (6 seconds for LOTRO I believe). This is most clearly seen when you one shot a mob and the mob, though showing no moral, is still standing there and then undergoes the death animation a few seconds after you hit them.
The only way to change this is to change the timing of the game (will never happen without a complete re-write of the game engine) and the timing of client updates.
Ujest - 140 Lore-master, Opun Tia – 107 Warden, Tummi - 105 Captain, Veneur - 75 Hunter, Cneasai - 66 Minstrel, plus alts and mules
Officer, Pipeweed and Ale, Arkenstone (formerly – Friends of Frodo, Vilya)
and Star Citizen…