QualityOne uses the Why object which is one of the core objects and object types to support the 5 Why's Analysis.
An admin set a value to the Justification field when updating a Why object record in Vault. Why is the value not saved successfully?
The Justification field can be saved if and only if the Why object record is marked as Expected.
Vault Help Documentation: Configuring 5 Whys Analysis (QualityOne)