I'm not opposed to the idea of having intentionally dumb AI, but seeing a necromancer with its back turned to me on an adjacent square zapping its minion in another room came off as a programming error more than anything else and was kind of immersion breaking imo.
I see. Thanks for the explanation. Still seems like flawed AI logic to me though. If the skeleton doesn't have valid attack target the necromancer should consider teleporting the minion, which it can already do.