Email notifications categories created on instances do not share the same sys_id. This could cause problems when moving notifications from one instance to another that will not be able to find a record in sys_notification_category table referenced on other instances

1. Upgrade to a release from Jakarta on 2 similar system (for example, cloned instances).
2. Export one notification from one of the upgrade systems and import it on the other system.
3. Open the notification on the new system 

Note that the Email Category is not displayed.

When you move a notification to a new instance, you need to reselect the notification category.

An advanced workaround is available:

1. Export the Email notification categories on sys_notification_category on the original instance.
2. On the target instance, import the sys_notification_category records exported before.
3. (optional) Re-associate the existing email notification to the imported sys_notification_category records.
4. (optional) Remove the unused sys_notification_category records.