Probably relay selection and encryption differences.

Raw JSON

{
  "kind": 1,
  "id": "0df492ea20e8b04a9b9b5d77e3ef32c2b2993ec9facb9e40f7e18ec5575b429d",
  "pubkey": "dd664d5e4016433a8cd69f005ae1480804351789b59de5af06276de65633d319",
  "created_at": 1787339196,
  "tags": [
    [
      "e",
      "9a656c90bf0f36c34a0daf90410fc8f114b6c51f19c47ccb12ebf127427b8fd2",
      "",
      "root",
      "dd664d5e4016433a8cd69f005ae1480804351789b59de5af06276de65633d319"
    ],
    [
      "e",
      "c4c807e30f2d8602b5b05ce6c93bc1a231d8209d5b1514bac33a14bc0d1317b7",
      "wss://nostr21.com/",
      "reply",
      "f33285217e976ad9caf0546445ad8107db98f65967cdce6cce45e60da00ee32a"
    ],
    [
      "p",
      "f33285217e976ad9caf0546445ad8107db98f65967cdce6cce45e60da00ee32a"
    ],
    [
      "p",
      "dd664d5e4016433a8cd69f005ae1480804351789b59de5af06276de65633d319"
    ],
    [
      "client",
      "imwald"
    ]
  ],
  "content": "Probably relay selection and encryption differences.",
  "sig": "8e58a499d5d67965d59f4b8a1d3d207560a335da7844a898ebd70b43b2c92172205a5cdeb3cb2f09b76f580522ce94136144d8098999c04e92a055c377bd8c09"
}