Hi @mills1979,
You'll need to correct the figures reported in your STP. The current & prior years will need adjusting to ensure data matching is correct.
When you refer to SGL, just to clarify terminology, do you mean:
The impact on you and your employee/s depends on what was actually paid to the employee’s super fund. If the correct super contributions were paid on time, this is a reporting error. This means, there would typically be no impact on the employee’s super balance and no SGC consequence.