When running a GET Computers REST API query against the Symantec Endpoint Protection Manager (SEPM), user mode clients wtihout a logged in user are not returned in the results. This behavior willl also result in these user mode clients not enrolling with Symantec Endpoint Detection and Response (SEDR).
This issue is fixed in Symantec Endpoint Protection 14.2 RU2 MP1. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec software here.