macs missing or losing IP inventory information

We are seeing somethign strange with our macs in Altiris 7.6.  we have about 10,000 macs under managment and it appears that many of them fail to report TPCIPv4 information in the course of the basic inventory.  manually running a basic inventory fixes this for a little while but they appear to lose this again shortly.

here is an example

there is no regular TCPIP information only v6.

this causes the macs to not report into the proper site and begin downloading straight from the NS package server with bad results.

Has anyone seen this behavior?

Here is a simple SQL report that will show you what machines have Null IP information

SELECT
   [vri3_Computer].[Guid] AS [_ItemGuid],
   [vri3_Computer].[Name],

[Inv_AeX_AC_TCPIP].[IP Address]


FROM
   [vRM_Computer_Item] AS [vri3_Computer] 

LEFT OUTER JOIN [Inv_AeX_AC_TCPIP]
         ON ([vri3_Computer].[Guid] = [Inv_AeX_AC_TCPIP].[_ResourceGuid])

WHERE
[Inv_AeX_AC_TCPIP].[IP Address] IS NULL