Performance Data Integrity Check Job

Summary

How do data issues identified even happen?

Content

We've recently learned about the Performance Data Integrity Check job that identifies data problems with data that impacts the documents.  We've been running it every so often and there are two data issue scenarios that we're really confused about.  I'm hoping someone out there can explain to me how these situations occur, because we're at a loss.

Once of the situations is that while an employee's document as a whole is showing as complete, there are individual steps/tasks that are not complete.  For example, the manager evaluation, share or worker final feedback tasks may not be complete.  How can this even happen?  How can the whole document show as complete if these individual tasks haven't been completed?  It's a linear progression through the tasks to ultimately get the document completed.  So we're really baffled as to what's happening with these.