Salary Download process has Replaced First Salary Date Data not Added a Row, Why? & How to Resolve?

Summary:

Employees eligible for a backdated pay increase, and where the Grade Rate Synchronization process errors dues to future dated rows, are updated using Salary Download. For some employees this has not worked as expected and we need to restore the Hire Salary data.

Content (please ensure you mask any confidential information):

We use the Salary Download process every year for inserting Salary rows from the date the data has changed, where the Grade Rates Synchronization process doesn't work. This year we have had 43 (out of 1100) where the Hire Salary Row has been Replaced with the inserted row. Now we are unable to add a row prior to the Update row so the Hire Salary data is missing, how would this happen and how do we resolve it?