EOFY Finalisation - Error code

I have recently finalised the Payroll for the EOFY and was not advised of any errors however, I have had 2 staff members advise me that their pay information is not "Tax Ready" and yet all other staff have received this advise. I have stumbled across a report that has advised me that the finalisation was received by the Tax Office with errors. I am surprised that I had not previously been advised of this?? It appears that these 2 staff members both ceased full time employment with us and then a week later recommenced in a casual role. The 2 staff members were terminated and the ATO advised and then their cards were reactivated as Casuals. The error Reason Code is "Cessation Date cannot be before the Commencement date". Does anyone know how to fix this??