Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 25099)
+++ wp-includes/general-template.php	(working copy)
@@ -358,7 +358,10 @@
 		$args['redirect_to'] = $redirect;
 	}
 
-	$lostpassword_url = add_query_arg( $args, network_site_url('wp-login.php', 'login') );
+	// If using WordPress multisite, use the user's primary blog (falling back to the current site when they don't have a primary blog)
+	$blog_id = ( is_multisite() && get_current_user_id() ) ? get_user_meta( get_current_user_id(), 'primary_blog', true ) : null;
+
+	$lostpassword_url = add_query_arg( $args, get_site_url( $blog_id, 'wp-login.php', 'login') );
 	return apply_filters( 'lostpassword_url', $lostpassword_url, $redirect );
 }