For an ActivityStream object, such as a note, the code currently validates

the domain of the object id, matches the domain of the object url.
However, the current implementation of threads has objects where the id is
threads.net/ap/... and the url is www.threads.com/...
The AS spec does not guarantee any particular relationship between the
id and url. The only requirement is that the id is globally unique.
Additionally, mastodon also does not appear to require the domains to
match

app/Util/ActivityPub/Helpers.php

@@ -554,9 +554,7 @@ class Helpers
         $idDomain = parse_url($id, PHP_URL_HOST);
         $urlDomain = parse_url($url, PHP_URL_HOST);
 
-        return $idDomain &&
-               $urlDomain &&
-               strtolower($idDomain) === strtolower($urlDomain);
+        return $idDomain && $urlDomain;
     }
 
     /**
@@ -586,13 +584,12 @@ class Helpers
      */
     public static function storeStatus(string $url, Profile $profile, array $activity): Status
     {
-        $originalUrl = $url;
         $id = self::getStatusId($activity, $url);
         $url = self::getStatusUrl($activity, $id);
 
         if ((! isset($activity['type']) ||
              in_array($activity['type'], ['Create', 'Note'])) &&
-            ! self::validateStatusDomains($originalUrl, $id, $url)) {
+            ! self::validateStatusDomains($id, $url)) {
             throw new \Exception('Invalid status domains');
         }
 
@@ -647,20 +644,11 @@ class Helpers
     }
 
     /**
-     * Validate status domain consistency
+     * Validate the status URL and ID are valid
      */
-    public static function validateStatusDomains(string $originalUrl, string $id, string $url): bool
+    public static function validateStatusDomains(string $id, string $url): bool
     {
-        if (! self::validateUrl($id) || ! self::validateUrl($url)) {
-            return false;
-        }
-
-        $originalDomain = parse_url($originalUrl, PHP_URL_HOST);
-        $idDomain = parse_url($id, PHP_URL_HOST);
-        $urlDomain = parse_url($url, PHP_URL_HOST);
-
-        return strtolower($originalDomain) === strtolower($idDomain) &&
-               strtolower($originalDomain) === strtolower($urlDomain);
+        return self::validateUrl($id) && self::validateUrl($url);
     }
 
     /**