Created a package, using the "Default Group" and set up the endpoint to report to the cloud console under that group. Later, an administrator may move the endpoint to another group for any environment specific requirement. If the administrator deletes the entry from the Symantec Endpoint Security Cloud (SESC) console without removing the SES agent from the endpoint, it will automatically be reported back to the "Default Group", not the last communicated group.
The SES agent is working by design. When a device is removed from the Symantec Endpoint Security Cloud (SESC) console, we lose all information about its group assignment prior to deletion. So, when the client reports back and the device is re-enrolled, it gets assigned to the same group as the installation package that was used to enroll it in the first place.