Here is a quick way to trouble shoot ITMU detection issues on a client.

Review this MSDN article: (http://msdn2.microsoft.com/en-us/library/aa387290.aspx) and save the VB
script locally and name it something (i.e. scantest.vbs), and the updated catalog
file to a machine you think is suspect.

Make sure you update the line in the script that reference the path and the
name of the cab. (by default, it’s the old cab name)

Run the script and pipe the output to a text file. (i.e. scantest.vbs >
results.txt)

If whatever update you are looking for shows up in the results
file, but not in SMS, then start troubleshooting SMS.

(I would start with the client log files, client WMI (Win32_PatchStateEx class), then follow the flow up the hierarchy.)

If the update doesn't show up in your results list, then it may be an issue
with the catalog itself, and you would need to open a case with CSS to help
investigate.