Hello Vaishak Nair  I don't know if this is the answer you are looking for, but if you review your search results closer, it is actually giving you both results but group together the properties for the device "CATOIF04".  Look at the "Serial #:" data, you have two serial numbers.  That indicates to me it did find both instances.  The quick search is limited to only look up "device" entities with only the properties "Type", "Desc.", "Model", "IP:", "Serial", and "Availability". At least that is my findings from my environment. (4.0.1)  So it is giving you both results technically, but not with enough context or in a format to easily identify there are 2 results.
I just noticed recently that when I search for a device (a virtual machine in my case) only one instance of it shows up in the results. We have two Virtual Machines with the same Device name (one Prod and one DR ) and only the DR device shows up in the quick search results.   Is there a way to work around this to get both of them to show up , apart from using the advanced search option ?  I am on v 4.0.1.  Thanks Vaishak
Question on Quick Search.