Board Thread:Manga/@comment-29465282-20161115162723/@comment-37897419-20181222233741

Old thread but this mystery is still ongoing.

In the most recent chapter it's been revealed as Eren tells Mikasa, that he was told by Zeke, that the headaches are caused by Ackermans going against their own blood to obey their host's orders... but I think OP's theory makes more sense and that Zeke is purely lying.

1st time might be because she was unable to obey Eren's command for her to help him save his mother.

2nd time might be because she tried to kill herself despite Eren's order for her to live and fight.

But what about all the other times? Eren hasn't given her any orders, nor is what she's doing at the moment contradicting the "live and fight" order.