diff --git src/bp-core/bp-core-filters.php src/bp-core/bp-core-filters.php
index ce335e8..5ac5f26 100644
--- src/bp-core/bp-core-filters.php
+++ src/bp-core/bp-core-filters.php
@@ -423,7 +423,7 @@ add_filter( 'wpmu_signup_user_notification', 'bp_core_activation_signup_user_not
  * @param string $seplocation Direction to display title.
  * @return string New page title.
  */
-function bp_modify_page_title( $title, $sep, $seplocation ) {
+function bp_modify_page_title( $title = '', $sep = '', $seplocation = '' ) {
 	global $bp;
 
 	// If this is not a BP page, just return the title produced by WP