ToME: the Tales of Maj'Eyal

When an enemy killed my summoned lightbringer (according to the log) in Dreadfell, it did not vanish, but remained on the map with 0 hp (0%).

I tried killing it myself, but the same thing happened: I got the message that I'd killed it, but it remained alive. Over time, it regenerates it's hp.

Note that I can still summon other lightbringers... but now I seem to always have that undying one in my party.

To clarify: this undying Lightbringer does not follow me around or anything. It stays in place, as Lightbringers do. But at the top of the screen, you can see it's little party icon no matter where you go.