Search Return error

Last week I noticed that I could no longer search in Person/Contact Maintenance, and would get an error saying "Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints."  I tried a couple of different things and ended up sending a support ticket to Epicor.  After going back and forth about this, he suggested that I run a simple BAQ in the PerCon table and see if there were any broken records, which I did and found no errors.  He then suggested that I try to run the search and limit it to 99 results instead of the default of 100.  It worked.  Why?  Has anyone else come across this?  (Of course I haven't gotten any sort of explanation from Epicor about this)