I have watched Fringe many times and I have always wondered how long did Walter know that Olivia was Olive from his FL trials? Have I just missed that bit of information or was that just glanced over? It's always been a plot hole for me!
Walter knows olivia is olive but he feels guilty. so untill season 4 he wont tell
Could be that the writers didn't know where they were headed.
What do you think?