SAP Note 10280 - Account assignment project or WBS element.

Symptom

The field project or WBS element is not displayed within the sales
order on the account assignment screen in the standard system for
the item category TPK.
Additional key words

Cause and prerequisites

The incorrect requirement class is used.
Depending on the consumption indicator from the requirement class
(T459k), the field is displayed or not.
Consumption indicator = P.
Solution

Check material with its requirements type and requirement class.

Key word: Acct assignment