Well, this is the first I've ever heard of this. I guess I've been going under the false assumption the council at nicean affirmed what the early church recognized as the 66 book canon. Although, I will say Catholics do introduce extrabiblical doctrine that does not exist as part of scripture. ie: Purgatory...there is no way you can justify being "Born Again" and praying for the dead's salvation. This is a direct contradiction, unless Catholics believe you can become "unborn again"?
But what about “backsliding” and “stumbling”? You’re not “unborn”, but you do run the risk of rejecting the grace given at baptism . . . .