It is possible to set the NoAutoShutdown flag globally using Set-ProvServiceConfigurationData or on individual Prov Schemes using Set-ProvSchemeMetadata. After upgrading to 2402 cu3, the NoAutoShutdown flag is not being honored. It will shows it is set but when the Preparation machine boots, it will complete its prep process and still shut down.
This is a known issue with both 2402 and 2507.
A patch has been created to address this issue. Please contact Citrix support to receive this patch.
After upgrading to CVAD 2402 CU3, the NoAutoShutdown flag is not being honored. The Preparation machine still shuts down.