A Linux Endpoint agent version 14.3 RU4 or later upgraded to a newer build when the administrator did not intend to upgrade the agent.
14.3 RU4 and later Linux Endpoint agent can be managed by multiple platforms.
This is by design.
In 14.3 RU4 and later, the Linux Endpoint(on-premise or cloud) agent can be managed by a Data Center Security (DCS) Manager and either Endpoint Protection Manager (SEPM) or Symantec Endpoint Security (SES cloud). This means if a Linux agent update is issued from DCS, then the Linux agent also reporting to the SEPM will show as updated. This single agent will honor the remote upgrade request from any of the supported management platforms.