What kind of soil / substrate is the wisteria planted in? Wist ferociously rips through substrate nutrients and depletes the general area pretty quickly. If it runs out of nutrition, it can experience die back. I haven't had this issue in fluval substrate with root tablets (gell caps filled with osmocote / peat / clay) - but I did before the addition of the root ferts.
Somtimes the cutting will just start to rot before roots have a chance to grow. You'll have a lot more success if the node right above your cut already has some roots growing. Trim those roots down to 2 cm, and clip any leaves off that will be within 1 inch of the substrate.