Basic Inventory does not report about all agent plug-ins to Notification Server because of missing agent registry keys. Without these present, only partial Basic Inventory plug-in information will be sent and the AeX AC Client Agent dataclass will lose registered plug-in information. This can also cause agents to fall out of Filters and Policies where plug-in information might be used.
The common symptom is that under Resource Manager or Manage>Computers>Symantec Management Agent Details, information regarding other plug-ins, with exception of the Altiris Inventory Agent, is missing:
Capturing the Basic Inventory NSE on the client machine doesn't show everything that is currently installed as far as plug-ins goes, but opening the Agent UI shows that there are more plug-ins installed.