The idea is that Catholicism quickly drifts very far away from its original roots; it's influenced by other religions, and the colonists come up with original ideas of their own.
I think this depends in large part on whether or not there's an institutional Church for the Catholics. Were there priests on the colony ship? More importantly, were there bishops? You need bishops to ordain more priests and more bishops. Without priests or bishops, I could see colonists abandoning orthodox Catholicism within several generations, but with bishops and oriests, I'd be surprised that there was anything more than a syncretistic folk Catholicism practiced by some by officially denounced.
Awesome story by the way. Very fun and interesting. I check often for updates. So far, we're getting the broad strokes, like a Wikipedia page. Any chance for more detailed histories at a later date?
Apostolic succession was maintained, yes. (In a manner of speaking, the apostolic succession was maintained later on through apostolic succession).
In that case, bishops weren't very successful in maintaining doctrinal purity - much of their success was probably due to their willingness to overlook differences. The religion ended up, indeed as syncretistic folk Catholicism, with official sanction.
Thanks for the interest btw. As for a detailed version, I'd love to! But I have millenia to cover, and not that much time to do it, so it probably won't be anytime too. (I also have fiction set in that setting, that I'd like to get out first.)