Candidate Missing from Hiring Manager View

Summary

Some candidate profiles do not appear in the Manager view

Content

We are using Taleo Recruiting and have recently added Hiring Managers to the requisition for viewing of candidates.  However, it doesn't appear that the HM can see all the candidates for positions.  Example:  As the Recruiter for one position I see 28 candidates and the HM only sees 18.  I tried to determine if there was a pattern and am coming up empty.  I thought maybe it was due to candidates that didn't finish the application process but that's not the case as the HM can see individuals that didn't submit.  Has anyone else experienced this?  Could there be a setting/role