Every time I change my check-in control, the changes I made keep reverting back to its previous setting. Why does it keep doing this?
There is a setting applied at the group level under System tab > Check-in Policy or Policy Management is applying the setting.
Go to the System tab > System Preferences > Check-in Policy and remove the 'Check-in' Period for the group.
If you are using Policy Management, go to Policy Management > Machines and hover your mouse over the scroll next to the agent icon. A new window will pop-up detailing what policy is applying the check-in settings. Locate that specific policy within the Policy Management > Policies section and you can edit the check-in control here.