https: social login redirection to http fails

My site has https login and administration.
After a social login the user is redirected to
https://www.example.com and not to the http version of the site. details:

site: http://www.example.com

https configuration in wp-config.php: define(‘FORCE_SSL_ADMIN’, true);

LoginRadius.com account duly configured w/ https.

Social login plugin configuration:
Login Redirection Setting: Redirect to the following url: http://www.example.com/

After a social login the user is redirected to
https://www.example.com

Do you think it’s a plugin bug?

http://ww.wp.xz.cn/extend/plugins/loginradius-for-wordpress/