quest lost knowledge first done, then failed?

[Jurriaan]

I just had the Quest 'Lost Knowledge' done, and interacted with Limmir to get a new ring,
then, when the demon unique had finished taking his bath in the moat, it ultimately failed
because he damaged Limmir too much while I was smashing him.

Now I can live with that, but 'done' sounds very final and it's somewhat surprising that
something can happen to that status afterwards. Shouldn't Limmir change that moat
into holy water or invite some friends when he's done?