First of all, when I first transplant very newly rooted cuttings, I make sure to
transplant with the original rootball as intact as possible. To me, any disturbance
of the tender roots has "bad" results; others have had better luck, and may think
otherwise. I am not sure what you did.
Second, I had undisturbed new leaved rootings, with the new leaves
very suddenly going limb and then the whole thing dies. On close examination,
the old hardwood cutting had just rotted somewhere between the roots and
leaves, thereby breaking the "plumbing" link between the two. Very rarely, I
managed to salvage such a cutting, by topping with more soil around the
the still healthy top part of twig together with a vented moisture dome..