SSO profiles to different Portal Access items on a full Webtop not working consistently

Here is my config under portal access list ACL order 0 - Resource is pointed to http://xyz.com/index.html - Basic Auth ACL order 1 - Resource is pointed to http://xyz.com/mypage.html - Basic Auth ACL order 2 - Resource is pointed to http://xyz.com/form.html - Form based auth

When I am clicking on 1st webtop i.e. http://xyz.com/index.html or on 3rd webtop i.e. http://xyz.com/mypage.html , SSO is successful. But when I click on webtop for my form based app , it prompts for credentials( SSO is failing because i is sending GET to my action uri instead of POST in first attempt ) . If I close that tab and click on my same webtop again , form based SSO starts working( because it is sending POST in second attempt) .

When form based sso starts to work , my basic SSO starts failing and other two webtops start prompting for credentials now

Any suggestions would be appreciated