Cookie is generated with wrong sid

Hi , 

We have sso set up with IWA (Zero degree sso) . We already have a 11i instance attached to this env. When logged in , it is correctly generating a cookie with the sid name.

Now , we have integrated another R12..1.3 instance that is upgraded from a 11i instance  and configured this instance with the existing sso env setup. When login , the sso functionality is working fine with IWA. But when i go and check the cookies that it generates , it is creating a cookie with wrong sid name . It is creating a cookie with the 11i instance sid from which it is upgraded. the whole functionality is working fine..