A Microsoft System Center 2012 or System Center 2012 R2 client installation (CCMSetup) initially fails and causes a client retry task to be registered in Windows Task Scheduler. After the client installation succeeds, the retry task is not deleted as expected. Therefore, the clients continue to reinstall every five hours.
In this situation, if you upgrade the System Center 2012 Configuration Manager infrastructure to System Center Configuration Manager Current Branch or Long-Term Servicing Branch, and if you do not upgrade the System Center 2012 Configuration Manager clients, the scheduled retry task continues to force a client reinstallation every five hours.
The next time that CCMSetup runs, the clients find an updated management point or distribution point, and they reinstall the client software. This upgrades the clients to System Center Configuration Manager.
These continual upgrades occur outside the normal upgrade process that is configured by the administrator. This includes the client piloting feature.
We have a new KB that describes this issue and gives options to resolve it and prevent an unwanted client upgrade For more information please see the following: