I'm at the point where I've returned to Brandon in Silverglen to give him the ore, but it's bugged out and he won't give me the Tenebrium skill.
Like many others, I did the mines first and picking up ore there created a quest update.
Brandon gives me the appropriate dialogue, but no Tenebrium skill.
I've had Bairdotr in the party since the start, so I wasn't sure if her Tenebrium skill was causing an issue.
I dropped her, and picked up Madora and at one point he gave only Madora the skill - so for some reason he's reading the rest of my party as having it.
I've tried a combination of things, sending the ore to homestead, getting rid of the ore from the mines (NPC vendor) getting rid of and re-acquiring the ore from the Troll King's cave.
Another odd point is that I is that I have 3 ore that for some reason won't stack with any other ore.
I'm at a loss of what to do at this point, it seems bizarre that such an important skill is buried in a quest with a bug that I can find people complaining about since July 2014 on Steam.
I know there is a skill book in the game, but that's only for one character - brandon should just give out 4 books on quest completion or something.