I don't know if this is a bug, but it was rather peculiar.
I was working on my last quest: Kill WarChant the Dark Elf before he builds a weather machine.
Then it said:
You win! Town saved.
There was no explanation. It just said 'failed'. I would expect to have a consequence for failing the quest, like the weather machine appearing, but nothing happened.
I don't mind winning
but it was rather strange.