Yes, really weird. I mean, revenants and arcane horrors are supposed to be
the elite undead according to the in-game lore.
OTOH it is not really surprising in a game that classifies brontos as 'human'..

In any case it's a pity that the runes don't work, because I wanted to wreak horrible revenge on revenant-kind for the harrowing battles that my first toon had to endure (Brecilian Forest right after Lothering, LOL). The blade was quite useful in Redcliffe, though, for cutting down most of the undead before they got near the kill-stealing bunch of nutters that you have to keep alive...