diff --git a/packages/backend/src/core/activitypub/type.ts b/packages/backend/src/core/activitypub/type.ts
index c14c6aa55f..6c77ef92d0 100644
--- a/packages/backend/src/core/activitypub/type.ts
+++ b/packages/backend/src/core/activitypub/type.ts
@@ -122,10 +122,6 @@ export function yumeNormalizeObject(object: IUnsanitizedObject): IObject {
 		object.url = yumeNormalizeRecursive(object.url);
 	}
 
-	if (object.attachment) {
-		object.attachment = object.attachment.map(yumeNormalizeRecursive);
-	}
-	
 	if (object.inReplyTo) {
 		object.inReplyTo = yumeNormalizeRecursive(object.inReplyTo);
 	}