Sometimes NPCs display hitsplat on respawn. Of course the hits bar should always display, but I don't remember this behaviour of displaying hitsplat post-death in 2003+. It does not occur every time, I'm not completely sure of the condition.
This might be authentic for the December 2001 client. Perhaps a good test is to see if the same behaviour occurs in client 204 protocol. If it is present there, I would say it is probably a server bug (queueing hitsplat when NPC is not alive to handle it) rather than emergent consequence of the network protocol.