Whenever you use the automatic payroll workflow, this workflow can be interrupted. This happens whenever a retroactive correction is performed or whenever there is an error in an action. Whenever the workflow period is interrupted, you must execute the following actions manually in that period. All actions will be processed automatically as usual for the period after that.
Whenever a pre-run is performed, the payroll workflow will continue as usual afterwards. As soon as the 'normal' run is performed to close out the period, the payroll workflow will be interrupted; the actions after that will then have to be executed manually.
Whenever you have an alert sent out in case of an error, you always know when these manual actions must be executed. This is the case when you are processing a retroactive correction or when you receive an error alert.