diff --git src/bp-core/bp-core-template.php src/bp-core/bp-core-template.php
index 54fe156..88b150b 100644
--- src/bp-core/bp-core-template.php
+++ src/bp-core/bp-core-template.php
@@ -3024,9 +3024,15 @@ function bp_get_the_post_class( $wp_classes = array() ) {
 	// removes the 'page' and 'type-page' post classes
 	// we need to remove these classes since they did not exist before we switched
 	// theme compat to use the 'page' post type
-	$page_key      = array_search( 'page',      $wp_classes );
+	$page_key = array_search( 'page', $wp_classes );
+	if ( $page_key !== false ) {
+		unset( $wp_classes[$page_key] );
+	}
+
 	$page_type_key = array_search( 'type-page', $wp_classes );
-	unset( $wp_classes[$page_key], $wp_classes[$page_type_key] );
+	if ( $page_type_key !== false ) {
+		unset( $wp_classes[$page_type_key] );
+	}
 
 	// okay let's merge!
 	return array_unique( array_merge( $bp_classes, $wp_classes ) );