There is definitely a reason to believe that not being indoctrinated is not the only way our party differs from the True Souls. When you do a mind meld with Gut, she sees something in you. I don't remember the dialog verbatim, but she calls it "strange shadows swimming around in your head" and offers to help remove them. Similar language, "Shadow Netherese magic", is used by Ethel when she tries to extract the tadpole. It's possible Gut senses this "shadow" magic in you and just can't identify it as Netherese. This is notable, because if every tadpole has been altered with these "shadows", Gut would have seen them in other True Souls and wouldn't have offered to remove ours. So it's possible that this Netherese Shadow magic is not just a standard modification all True Souls have, but something unique to our party.
This is pure conjecture of course, but everything regarding the tadpoles is at this stage. It's something of a running theme in the game: there are a lot of factions involved in this conflict, and none of them have complete or reliable information.
