Symptoms

I have a people picker on a form that has been working for awhile. It's data source is the SharePoint Integration People Picker smartobject that is auto created. When I load the form in a workflow task, I receive a "Smartobject name with GetPrincipals not found, rerun the registration wizard" error. I have tried to run the registration wizard but it did not resolve the issue.
 

Diagnoses

While we could not diagnose what caused the issue, it does seem to be related to a possible change made on the SharePoint side of things.
 

Resolution

We deleted and re-added the Picker and configured it the same way. The issue did not show up again.