Openfire sends empty (without stamp attr) jabber❌delay extension to smack

Openfire Openfire Support
1

I receive offline message from openfire server, but it contains empty jabber:x:delay extension.

The message I receive is:

<message id="qU7N8-64" to="ac1@server.jj.ru" from="ac2@server.jj.ru/4847791" type="chat">
      <body>test message</body>
      <delay xmlns="urn:xmpp:delay"></delay>
      <x xmlns="jabber:x:delay"></x>
</message>

This message I receive with smack library.

But when I connect to openfire with Miranda IM, openfire sends extension jabber:x:delay with data (with stamp attr)

Why openfire sends empty jabber:x:delay only to smack library?