I have had some cuttings do just such that.
One day they are very healthy and the next day the leaves do "limp".
Close examination, showed that the "twig" got rotten somewhere
between the roots and the leaves, thereby breaking the plant
"plumbing" system. Over-water is the main rotting cause.
I was able to salvage very few cuttings by upping the soil
and doming the plant (the upper part may still have some life left in it?).
Unless the plant is very precious, it may not be worth the effort;
usually it is a goner. We all live and learn...