Symantec Endpoint Protection Managers (SEPM) are updating internally using LiveUpdate Administrator (LUA). The Symantec Endpoint Protection (SEP) clients pull updates directly from the SEPMs. The SEPMs are running a newer version than the clients and though the LUA is providing content for the versions that the clients are using, the LUA content download/distribution schedules have not been updated to pull content that matches the SEPMs version. The result is clients not updating some or all content when the SEPM is the update source.
Release :SEP 14.x
Component :LiveUpdate Administrator
In order to create content files for clients, the SEPM needs to be receiving SEPM content updates from the LUA that match the installed version on the SEPM (not the clients). For instance, if the SEPM is running 14.3 and the clients are running 14.2 and older, the SEPM would still need to download 14.3 content in order to accommodate the content file creation process for SEP client update requests.
Create new (or modify existing) Download/Distribution schedules in the LUA to include content that matches the version installed on the SEPM.
https://knowledge.broadcom.com/external/article/151320/install-and-configure-liveupdate-adminis.html