Liath’s Tower quest says it gives 1 passive skill point as a reward.
I just completed the quest and did not get said skill point. I’m sure, because that was the reason I went out of my way to do this quest.
Quest now shows as complete and still says I should have gotten 1 passive skill point.
You are capped at getting 15 passive points from quest rewards but there are 21 available from quests (this is to allow you to be able to skip some side quests if you wish). If you did all the quests in order Alric’s Revenge would have given you your 15th. Most likely not a bug. You can check how many you have from quests on the map screen in the bottom left.