Minthara never got yanked, she was not infested by a tadpole the same way were were.
You know this? Source? I agree she wasn't on our ship, but others, earlier?
I mean it is made pretty clear as you play the game that most characters with tadpoles do not know they have tadpoles, and they think they were instead chosen by the absolute. So certain characters are given tadpoles as gifts to empower them, Minthara is one of them. If I remember right the corpse of the drow in the druid grove gives you some more information on this too.
