diff --git a/wp-includes/block-supports/typography.php b/wp-includes/block-supports/typography.php
index 78c8b0a2ff..34345ca4ec 100644
--- a/wp-includes/block-supports/typography.php
+++ b/wp-includes/block-supports/typography.php
@@ -517,7 +517,7 @@ function wp_get_typography_font_size_value( $preset, $should_use_fluid_typograph
 		: array();
 
 	// Defaults.
-	$default_maximum_viewport_width       = isset( $layout_settings['wideSize'] ) ? $layout_settings['wideSize'] : '1600px';
+	$default_maximum_viewport_width       = isset( $layout_settings['wideSize'] ) && ! empty( wp_get_typography_value_and_unit( $layout_settings['wideSize'] ) ) ? $layout_settings['wideSize'] : '1600px';
 	$default_minimum_viewport_width       = '320px';
 	$default_minimum_font_size_factor_max = 0.75;
 	$default_minimum_font_size_factor_min = 0.25;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 42c46a983d..f0d4596291 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3.2-alpha-56685';
+$wp_version = '6.3.2-alpha-56737';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.