3568786 - Get error message IM421 "Notification type not defined" when saving quality notification in Change Quality Notification app

Get error message IM421 "Notification type not defined" when saving quality notification in Change Quality Notification app.
A prerequisite for this is there is an active implementation of BADI_QQM_NOTIF_EVENT_SAVE_CLD in your system.

SAP S/4HANA Cloud Public Edition

The issue is caused by incomplete coding in the BADI implementation of BADI_QQM_NOTIF_EVENT_SAVE_CLD. 
The interface of the BADI contains a couple of so called importing parameter (starting with IS or IT) which contains the current data of the notification. The changing parameters (starting with CS or CT) can be used to pass changes to the SAP coding. Whenever a customer implementation is using such CS or CT parameter, the current data must be taken before from the corresponding IS or IT parameter. Otherwise there will be no initial data in the changing parameters.

Put such data passing statements at the beginning of your code. For example:
CS_QNOTIF_HEADER = IS_QNOTIF_HEADER.
CT_QNOTIF_TASKS = IT_QNOTIF_TASKS.
Your code can only contain the parameters that you actually use.

IM421,Notification type not defined, Quality Notifications, BADI implementation, BADI_QQM_NOTIF_EVENT_SAVE_CLD IS_QNOTIF_HEADER, CS_QNOTIF_HEADER, changing parameters, importing parameters , KBA , QM-QN-2CL , Quality Notifications (Public Cloud) , Problem