Infallibility and transubstantion, among many other doctrines, were not formally declared to be doctrines until it became necessary to do so, due to some challenge or other. That's how some beliefs that had been around since the Apostles were not explicitly declared to be doctrines until many centuries later, at which point they were not invented but declared to be doctrinal.
I'm surprised you didn't know that.
Are you really?
Most former Catholics (I once was found, but now I'm lost) have a deeply shallow understanding of their former religion.
SD