diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index cefe9cfbb5..f59fb1b485 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -184,7 +184,7 @@ function render_block( $block ) {
 	 * @param array  $block      The block being rendered.
 	 */
 	$pre_render = apply_filters( 'pre_render_block', null, $block );
-	if ( is_null( $pre_render ) ) {
+	if ( ! is_null( $pre_render ) ) {
 		return $pre_render;
 	}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index fe88ba30f5..81fe86670e 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44554';
+$wp_version = '5.1-alpha-44555';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.