Recently, there have been concerns about released undead. In order to create a defensive cluster of undead/prepare for an incoming mob attack, I often use this tool to maximize the amount of undead I can have at disposal. In the aftermath of these things, however, and if the released undead are still intact, they are quite a bother to other players.
They don't appear to have an AI fit for persistence, and never de-spawn, tending to make them permanently lodged at transitions. This, coupled with the fact that some variants spam knockdown warrants unfair deaths for some players.
I suggest something is implemented to circumvent it. Perhaps a timer of destruction once the necromancer has left the area would fix this -- or perhaps they could be given a monster AI, and de-spawn like other monsters do.
I'd call that the price of making so many undead, tbh.
They are by intention and purpose such creations, and per say "mindless" left to their hunger and few lingering commands. Creator needs to use care when using them. Though I gues some changes could be made if we decide so.