I think it works as much as it can. Think about this for a moment. When a mob attacks you, it has to do a pathfind to you and then initiate a set of actions once its in a certain range. That’s how every engaged entity on a server works.
Now when they disengage (or tether as you all call it) they have to reverse course. Funcom chose the simplest way to make this happen. Why? Because when you agro everything in New Asgarath, or accidently punch a guard in Sepermeru and invariably run the hell away. There needs to be a simple function for now dozens of NPCs to return home without bogging down the server.
Would FC love to do some sort of complex AI that makes NPCs indistinguishable from players in their decision making? Sure they would. But that’s a fantasy. The reality of the situation is when a player disengages from a NPC, the NPC no longer needs to do any sort of complex calculations on how to attack or follow.
So when a player decides to run away or kite the enemy for over 10 minutes, its going to simply go back ‘home’ for the next adventurer to deal with. This is also why number 2 happens. If the pathing back just fails for whatever reason, the server gives up on the NPC. It has hundreds of other entities to worry about, consider it a write off.
As for massive healing. I dunno about you, but this happens to me whenever I get back to my base after a nasty fight. My HP usually goes from nearly nothing, to full in a few seconds. Course I have methods of doing this. If that breaks your immersion. Well it broke then. There’s still people who believe you should be able to do this to yourself in combat. So consider it a compromise.
But again, I don’t know what it is you all are doing that is triggering this all so often that its a problem. Or are you suggesting that when you ride across the lands that you expect to have the several dozen rocknoses, crocs, wolves, and whatever else still following you back to your base?
Because I seriously think you all are conflating a feature with a bug. Because for me, I literally need to run away for several minutes (without doing damage) to get a NPC to reset. In addition I need to run quite far (like half a grid square).
If you all think you should be able to run a NPC halfway across the map for like 10 minutes or more. You’re simply be unreasonable.