fix the cache key to properly use the dynamic post ID

includes/classes/DistributorPost.php

@@ -666,7 +666,9 @@ protected function parse_media_blocks() {
 		$found = false;
 
 		// Note: changes to the cache key or group should be reflected in `includes/settings.php`
-		$media = wp_cache_get( 'dt_media::{$post_id}', 'dt::post', false, $found );
+		$cache_key   = "dt_media::{$this->post->ID}";
+		$cache_group = 'dt::post';
+		$media       = wp_cache_get( $cache_key, $cache_group, false, $found );
 
 		if ( ! $found ) {
 			// Parse blocks to determine attached media.
@@ -679,7 +681,7 @@ protected function parse_media_blocks() {
 			}
 
 			// Only the IDs are cached to keep the cache size down.
-			wp_cache_set( 'dt_media::{$post_id}', $media, 'dt::post' );
+			wp_cache_set( $cache_key, $media, $cache_group );
 		}
 
 		/*