Hi Arun,
I have the same behaviour on my machine :
System Updates inventory is collected using following WMI query :
SELECT * FROM Win32_QuickFixEngineering
Inside this class, the Install Date is stored but not the time.
We could confirm this by checking Installed Updates under "Control Panel/Programs/Program and Features/Installed Updates" :
As the install time is not stored by Windows, it appears as 12:00am In ITCM inventory.
Thanks.
Regards,
Jean-Yves