Li T'ieh-Kuai the Longdead Legionnaire

[Vynd]

The fact that you were holding Tien Chi's capital, where Li T'ieh-Kuai normally would have respawned, could be significant. Or it could be a coincidence.

[Sheap]

The glitch can only affect immortals that don't get resurrected through normal immortality, so holding the tien chi capital could very well have been significant, unless the battle also occurred outside of tien chi dominion.

[Molog]

Twiceborn and ritual of returning also seem to be able to cause this bug.