1. The original idea was there should be a compendium available to Bishops to aid them in developing their own local catechisms.
2. This became was converted into a universal catechism .. forgetting that the language had been designed for theologically trained recipients ( = bishops) ... yet now it was offered to everyone.
3. The Catechism was ready to go to press in english, when publishers were told to stop the presses.  They then had to wait until an new English translation was given to them.  This was the first victory of the literalist school of translation ... Most noticeable in the new translation was the elimination of inclusive language.
So I would say, if you remember who were the original intended recipients, then that kind of book might produce relatively quickly. But if it was meant to be a book for everyone, then, indeed, if was doubly mangled: first, in terms of not taking the time to adapt the text appropriately; secondly, in terms of the enforced English translation.