pickerFieldUsers groupFilter not working for Non Group member

Hi

I have facing issue for below scenario

1. I have a group lest say Group G1 and User U1 and U2 are member of this group.
2. Group G1 Visibility is Public,privacy policy is Low
3. I have one U3 user which is bit part of Group A
4. I created a interface with pickerFieldUsers and used the Group G1 in group filter

When I log in with the system admin user lets say U4 i can see U1 and U2 which are part of Group G1. However if I log in with the user U3 which is not part of Group G1 and not a system admin I am not able to see the any user

I have made everyone as admin in group security

Thanks
Ajinkys