Community Auth - Login error if autoload form_validation library

Hello,

I am encountering a strange problem with Community Auth.

Multiple login attempts fail when I autoload application dependent libraries like this - $autoload['libraries'] = array('database','form_validation');

This results in an empty 'form_token'.

The issue is limited to auto loading 'form_validation' only.  Login succeeds as soon as I remove 'form_validation' from the auto load array.

I am using the default "demo" login to test Community Auth with no changes to the controller or views except for the config changes mentioned in the installation steps.

Could someone suggest what could possibly be the issue? 

Thanks and Regards,
Venkat