For this issue uncheck the Restore original group membership on the option for Default rules for the Undo Deprovisioning operation.
You can navigate to that setting by using the following steps:
In ARS MMC Console, navigate to:
Active Roles Server | Configuration | Policies | Builtin | Advanced | Built-in Policy - Default Rules to Undo User Deprovisioning
Double-click on the policy then select the 'Policies' tab, then highlight the Default rules for the Undo Deprovisioning operation and click on 'View/Edit'. Select the 'Options' tab and uncheck Restore original group membership.