I have only done through chapter 2, but the forge of heavens quest is complete after updating my quest book.

Nothing I can do about this unfortunately, but it should be rare that it happens.

I think this is because it is quest ID 17 - so if you completed the quest that used to have ID 17, this is completed - i think it might be the ore and dowsing rod quest

That actually makes a lot of sense, sometimes an old quest gets deleted and a new one takes its place.