The notion of “infallibility” is totally unique in and of itself.
In the past hundred years, the Church has spoken twice with the strength of infallibility and both had to do with teachings on Mary.
You can discuss and debate what is written in any of our catechisms. The words in these books do not merit the descriptor: “infallible”.
There are authors and there are staff writers and there are translators and when you re-issue a particular printing of any catechism, you may encounter changes … but an infallible doctrine or dogma … may have new words, but the essence of the teaching will remain infallible.
But teachings such as the few on Mary are described as infallible.
We just do not use the word “infallible” casually … to explain or clarify what is written in one book or another.
I would refer, again, to one of Karl Keating’s books:
There are many good and excellent books and good and excellent writers.
But the idea of “infallible” does not hinge on the specific choice of words found in any specific book, so that one book might be infallible and another might not be infallible.
Scroll down to the article from U.S. Catholic on infallible teachings … which are those that are “ex cathedra”.