After a Software Update Point (SUP) synchronization with Windows Software Update Services (WSUS) is complete, software updates that were previously successfully deployed are displayed unexpectedly as invalid in the Administrator Console in Microsoft System Center Configuration Manager 2007. Specifically, the invalid updates icon (a red arrow) appears alongside the updates when you view the updates in the Deployment Management node of the Administrator Console. Additionally, these updates are no longer listed under the Deployment Packages node.
This issue may occur because of changes that were made to the Microsoft Update service in October 2012. These improvements contain metadata updates that affect all WSUS servers. These changes caused some updates to be marked as having a content change, even though the update binaries were not changed. For some administrators, the metadata changes may have been applied automatically when WSUS synchronized with the Microsoft Update servers in October. Other administrators received the changes by applying update 2734608 to their WSUS servers.
More info here :
KB 2783466: Software updates are displayed as invalid unexpectedly in the Administrator Console in System Center Configuration Manager 2007
Hope it helps ,
Kenny Buntinx