I was told by a priest, so that could very well be his reading of Vatican II documents. It wasn’t a declaration of the pope. “Limbo” could very well describe the emerging of the truth on this question: the truth was waiting for further revelation. Think of it that way, maybe, instead of it once being true and now it isn’t or that the Church made an error. It was the doctrine that was in limbo, perhaps, not the children.
Wondering who added all the keywords?????