Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 19546)
+++ wp-includes/ms-functions.php	(working copy)
@@ -323,10 +323,11 @@
 	if ( $link == false ) {
 		switch_to_blog( $_blog_id );
 		$link = get_permalink( $post_id );
+		$link = str_replace( 'https://', 'http://', $link );
 		restore_current_blog();
 		wp_cache_add( $key, $link, 'site-options', 360 );
 	}
-	return $link;
+	return apply_filters( 'get_blog_permalink', $link );
 }
 
 /**