If you have made any changes in your workflow (Manage Levels), you must always reconcile your references after in order to retroactively apply that change to all the references in your Project.
Reconciling your references does not modify your references or data.
A common example is changing the Users Needed to Process/Exclude from 1 to 2 reviewers and assigning your second user as a reviewer for the Level (after the first reviewer has reviewed some or all the references, in many cases). Once this is done, you would expect reviewer #2 to see unreviewed references on their Dashboard as a spot for them to review has been added.
If they do not see any changes, the first step should be to reconcile references and check the Reference Status Report to make sure your formerly fully reviewed references are in the "Some Reviews" column of this report.