Thanks for your reply jenniek,
The issue has happened to all our employees, not just a couple, which means we are going to have to change all the annual leave balances manually.
did you print the leave detail or summary report before you were converted from Essentials Payroll?
We were not informed that we were going to be converted from the Essentials Payroll to the new version which we would not have wanted to do anyway as this new system has many faults and it seems there is no way to go back to using the Essentials Payroll.
Also, when we try to view what the employees' old annual leave balance was, it has updated it to the new balance. The pay slips we sent when we did the payroll with Essentials Payroll showed the correct annual leave balance, but now, when we look at the past pay slips with the new payroll system, it has changed their balances to be the new (but incorrect) amounts.
It was a known issue that if you ran extra payruns in Essentials Payroll - another weeks leave would be accrued regardless of the date range being the same.
This was not an issue with Essentials Payroll, the issue was converting to the new payroll system. Additionally, the problem is not with the accrued annual leave, that is completely correct. The problem is with the current annual leave balance which should never increase (unless an employee reaches their holiday anniversary (which they haven't)). This should only decrease when the employee uses annual leave. However this has affected all our employees, even those who haven't taken any annual leave.
I think the only way for us to fix this is going to be manually calculating it based on our original payroll system, and then switching to a new payroll provider. Especially with all the bad feedback and our own experience using this new update downgrade.