If employees are still able to add or amend hours on Timesheets after the pay period is closed, this is usually due to the 'Maintain Historical Hours' access privilege being enabled on their System User Account.
When this setting is active, employees can modify timesheet data regardless of the period status.
How to Disable 'Maintain Historical Hours'
To remove this access, follow the steps below in Portal:
Go to WFM Admin Dashboard.
Click WFM Configuration.
Select WFM System Users Configuration.
Query the Employee in question.
Select Access Privilege.
Disable the parameter:
Maintain Historical Hours.Click Save.