.aba file sent payroll to incorrect bank accounts.

I have successfully used .aba to electronically transfer payroll for 3 consecutive weeks, however this time 2 employees payroll deposits were swapped over?
Nothing has changed. The .aba file was downloaded from myob and uploaded to my cba account, so I absolutely can't understand how this malfunction could've happened?
Has anyone else ever experienced this or know how I can avoid this in the future?
Thank you.