Symptoms

Destination user "A" share task to user "B" than user "B" approve task. when we trace the destination user echo "A" is the user take action "Approve" instead.
 

Resolution

This behavior is by design. When you delegate a task, the responsibility and owner of the task still ultimately lies with the destination user configured in the destination rule in your workflow. Thus, when you use the activity destination instance, the destination user name that is stored in the database will be the original user assigned the task and not the name of the delegated user.

As a workaround, in your smartform, you can add a rule “after the worklist item is submitted” and execute a smartobject method to store the current user’s name (under system values in context browser) into your database.