I accidentally screwed up with the Necromancers in the tower by breaking or absorbing one of the source jars from Braccus's vault.
So when I did get into the Necromancer Tower, the Lizard necromancer was dead on the ground. Because one was dead, the conversation did not progress far, and after a couple lines, talking to them produced [Met, has not given permission] as the dialogue text.
I eventually realized that I could just kill these guys manually, and surely enough, one had a key on them. But after I killed both of them, they all resurrected a second later - including the Lizard necromancer who had died when I broke their soul jar! That's a pretty clear error.
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Nearby, if you teleport someone into the source puddle, it triggers a trap and when they get teleported back, it releases an angry zombie. So angry in fact, that it walks through apparently solid bars to get to you.