Ticket #14949: 14949-current-user-can-not-login-before-logout.patch

wp-login.php

@@ -531 +531 @@
         if ( !$secure_cookie && is_ssl() && force_ssl_login() && !force_ssl_admin() && ( 0 !== strpos($redirect_to, 'https') ) && ( 0 === strpos($redirect_to, 'http') ) )
                 $secure_cookie = false;
 
-        $user = wp_signon('', $secure_cookie);
+        if ( is_user_logged_in() ) {
+                $user = wp_get_current_user();
+        } else {
+                $user = wp_signon('', $secure_cookie);
+        }
 
         $redirect_to = apply_filters('login_redirect', $redirect_to, isset( $_REQUEST['redirect_to'] ) ? $_REQUEST['redirect_to'] : '', $user);