diff --git a/wp-includes/block-patterns.php b/wp-includes/block-patterns.php
index dd70d2b589..a1a7a67d81 100644
--- a/wp-includes/block-patterns.php
+++ b/wp-includes/block-patterns.php
@@ -350,9 +350,25 @@ function _register_theme_block_patterns() {
 				continue;
 			}
 
+			$file_path = $dirpath . $file;
+
+			if ( ! file_exists( $file_path ) ) {
+				_doing_it_wrong(
+					__FUNCTION__,
+					sprintf(
+						/* translators: %s: file name. */
+						__( 'Could not register file "%s" as a block pattern as the file does not exist.' ),
+						$file
+					),
+					'6.4.0'
+				);
+				$theme->delete_pattern_cache();
+				continue;
+			}
+
 			// The actual pattern content is the output of the file.
 			ob_start();
-			include $dirpath . $file;
+			include $file_path;
 			$pattern_data['content'] = ob_get_clean();
 			if ( ! $pattern_data['content'] ) {
 				continue;
@@ -408,11 +424,13 @@ add_action( 'init', '_register_theme_block_patterns' );
 function _wp_get_block_patterns( WP_Theme $theme ) {
 	$can_use_cached = ! wp_is_development_mode( 'theme' );
 
-	if ( $can_use_cached ) {
-		$pattern_data = $theme->get_pattern_cache();
-		if ( is_array( $pattern_data ) ) {
+	$pattern_data = $theme->get_pattern_cache();
+	if ( is_array( $pattern_data ) ) {
+		if ( $can_use_cached ) {
 			return $pattern_data;
 		}
+		// If in development mode, clear pattern cache.
+		$theme->delete_pattern_cache();
 	}
 
 	$dirpath      = $theme->get_stylesheet_directory() . '/patterns/';
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f8222f9434..92596d3dc9 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-beta4-56930';
+$wp_version = '6.4-beta4-56931';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.