Notification service does not get the entire payload as input to send the event. It fetches the anchor payload using the dataspace and anchor name, provided as input. Hence, the actual payload or change depends on when data is fetched by the notification service instead of the initial change request.

This can be an issue if ever, for the same anchor, the core is able to complete several consecutive changes faster than what notification service can send, then some changes are not going to be published, only the latest/current would be.

Agreed with the team:-  

Workaround: In the Istanbul release, async processing will be disabled by default and can be enabled by setting 'notification.async.enabled = true' in the application properties.

Solution: In the next release, we can investigate more on partial data updates.