We are using OOTB Status Rport object with few custom attributes. One of these attributes is status. If the status is set to final, process is trigged and all attributes on the status report are locked. When you navigate back to this instance, where all attributes are locked and hit save the value of last_updated_date is changed, even though nobody changed (update) anything. If you do not update or change any attribute, the last_updated_date must not change.
This behavior is by design even if you do not update or change any attribute, the last_updated_date changes since the user with portlet edit rights will see the save button and this permission will allow a user to view and edit the definition of user defined portlets in application.
Steps to reproduce:
1- Open the Clarity portlet (Data Provider: Status Report)
2- Do not make any changes to the portlet data
3- Hit the Save button
Expected results: Last Updated Date does not get updated
Actual results: The value of last_updated_date is changed (to the current date) even though nobody changed (update) anything.
Testing was also performed on different OOTB portlets/data providers like Project object and Custom object as well, and they all show the same behavior of clicking save will show last updated date. Therefore if you want to track specific updates the best way is to use audit.