diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index 79f2b3eab3..58905d6822 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -1231,6 +1231,8 @@ final class WP_Customize_Manager {
 						$settings = $settings->getArrayCopy();
 					}
 
+					unset( $settings['_multiwidget'] );
+
 					// Find the max widget number for this type.
 					$widget_numbers = array_keys( $settings );
 					if ( count( $widget_numbers ) > 0 ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a29f298caf..2530a4f4e5 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-49075';
+$wp_version = '5.6-alpha-49076';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.