Conflicting Date error in Employee DBA Instructions

We have had several instances where employees have had Conflicting Date Errors in their employee dba instructions and dbas higher than the one with the conflicting dates did not calculate during payroll.  Can anyone confirm to me that this is true to design?  I believe this is happening when someone makes a change directly through Enrollment Overrides, but as I'm not there when its being done, I can not confirm. Is anyone able to provide a brief understanding of the anatomy of the system? 

Our employees do there enrollments through ESS, and 98% of the time our benefits coordinator verifies enrollments and makes adjustments if needed in the work file before the upload to live tables happens.  At times, there is a nered for her to make changes using enrollment with eligibility to an employee enrollment before the deductions are taken on the first check.  At times, she has used Enrollment Overrides to adjust enrollment info and I'm trying to determine if that's where the issue is arising.