Sorry about this, but I think it's belongs here instead of spoiler section. It's more about changelog than the quest.

The 1.4 changlog says that 'The White Phial' quest will start properly now, even after you have a Briarheart in your inventory, but 'The White Phial' quest has nothing to do with a Briarheart. 'Repairing the Phial' quest does. Did they mean 'Repairing the Phial' here? I'm having a problem with a Briarheart at the moment. If the patch is going to fix this, it will affect a lot of my decisions, and I might decide to just wait. If not, then I'll go ahead and do what I thought I should. Any answers are welcomed. But an official answer will be greatly appreciated.

I may be wrong bu isn't that a subquest and the quest line is called white phial?

It's definitely a seperate quest. And I'm not sure two quests are enough to be called a questline. Anyway, thanks for trying.