diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index 527289901e..3b0875f876 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -2292,7 +2292,39 @@ function get_calendar( $args = array() ) {
 	 */
 	$args = apply_filters( 'get_calendar_args', wp_parse_args( $args, $defaults ) );
 
-	$key   = md5( $m . $monthnum . $year );
+	if ( ! post_type_exists( $args['post_type'] ) ) {
+		$args['post_type'] = 'post';
+	}
+
+	$w = 0;
+	if ( isset( $_GET['w'] ) ) {
+		$w = (int) $_GET['w'];
+	}
+
+	/*
+	 * Normalize the cache key.
+	 *
+	 * The following ensures the same cache key is used for the same parameter
+	 * and parameter equivalents. This prevents `post_type > post, initial > true`
+	 * from generating a different key from the same values in the reverse order.
+	 *
+	 * `display` is excluded from the cache key as the cache contains the same
+	 * HTML regardless of this functions need to echo or return the output.
+	 *
+	 * The global values contain data generated by the URL querystring variables.
+	 */
+	$cache_args = $args;
+	unset( $cache_args['display'] );
+
+	$cache_args['globals'] = array(
+		'm'        => $m,
+		'monthnum' => $monthnum,
+		'year'     => $year,
+		'week'     => $w,
+	);
+
+	wp_recursive_ksort( $cache_args );
+	$key   = md5( serialize( $cache_args ) );
 	$cache = wp_cache_get( 'get_calendar', 'calendar' );
 
 	if ( $cache && is_array( $cache ) && isset( $cache[ $key ] ) ) {
@@ -2312,9 +2344,6 @@ function get_calendar( $args = array() ) {
 	}
 
 	$post_type = $args['post_type'];
-	if ( ! post_type_exists( $post_type ) ) {
-		$post_type = 'post';
-	}
 
 	// Quick check. If we have no posts at all, abort!
 	if ( ! $posts ) {
@@ -2327,9 +2356,6 @@ function get_calendar( $args = array() ) {
 		}
 	}
 
-	if ( isset( $_GET['w'] ) ) {
-		$w = (int) $_GET['w'];
-	}
 	// week_begins = 0 stands for Sunday.
 	$week_begins = (int) get_option( 'start_of_week' );
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index fb94dec7f8..7eb71f3a75 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.8-beta1-59938';
+$wp_version = '6.8-beta1-59939';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.