Hi Wasique,
There are 2 ways to discover IE;
1)Through CA Intellisigs which depends on the "Browsers" Intellisig to detect multiple Browsers and versions automatically including IE.
2)Through CA Provided XML based signatures which is the traditional way of discovering IE.
There are filters in the Client Automation Explorer UI to check the appropriate source of detection. You can also right click on a discovered release and go for Details and check the "Discovery Source".
The reason why two IE signatures are getting discovered is due to the fact that both the above discovery methods are active.
I tried to reproduce the problem by installing IE 11 on Windows 7 (64-bit) and Windows 2008 R2 in our lab and the discovery seems to be fine.
Please open a support case so that this can be looked into further.
Regards,
Subrat