Messages edited in Element show up as dupplications with an asterisk

[OliveiraHermogenes]

The issue is illustrated below:

Server: Synapse 1.93 (package from the main Debian repositories)
Operating System: Debian sid

The issue shows up in Populus when one edits a message from Element (and some other clients), but not the other way around. Here is the event from one of the edited messages above, as seems from Element:

{
  "type": "m.room.message",
  "sender": "@hermogenes:jaguatirica.pontofixo.net.br",
  "content": {
    "msgtype": "m.text",
    "body": " * Therefore, \\(\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}\\). But, since \\(\\phi\\) is an arbitrary formula of \\(L\\) and \\(\\Delta_{0}\\) contains only intuitionistic formulas, this equivalence in \\(L\\) contradicts the assumption that \\(L\\) properly extends intuitionistic logic.",
    "m.new_content": {
      "msgtype": "m.text",
      "body": "Therefore, \\(\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}\\). But, since \\(\\phi\\) is an arbitrary formula of \\(L\\) and \\(\\Delta_{0}\\) contains only intuitionistic formulas, this equivalence in \\(L\\) contradicts the assumption that \\(L\\) properly extends intuitionistic logic.",
      "format": "org.matrix.custom.html",
      "formatted_body": "Therefore, <span data-mx-maths=\"\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}\"><code>\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}</code></span>. But, since <span data-mx-maths=\"\\phi\"><code>\\phi</code></span> is an arbitrary formula of <span data-mx-maths=\"L\"><code>L</code></span> and <span data-mx-maths=\"\\Delta_{0}\"><code>\\Delta_{0}</code></span> contains only intuitionistic formulas, this equivalence in <span data-mx-maths=\"L\"><code>L</code></span> contradicts the assumption that <span data-mx-maths=\"L\"><code>L</code></span> properly extends intuitionistic logic.",
      "m.mentions": {}
    },
    "format": "org.matrix.custom.html",
    "formatted_body": " * Therefore, <span data-mx-maths=\"\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}\"><code>\\mathcal{B},v\\Vdash\\phi\\leftrightarrow\\bigwedge\\Delta_{0}</code></span>. But, since <span data-mx-maths=\"\\phi\"><code>\\phi</code></span> is an arbitrary formula of <span data-mx-maths=\"L\"><code>L</code></span> and <span data-mx-maths=\"\\Delta_{0}\"><code>\\Delta_{0}</code></span> contains only intuitionistic formulas, this equivalence in <span data-mx-maths=\"L\"><code>L</code></span> contradicts the assumption that <span data-mx-maths=\"L\"><code>L</code></span> properly extends intuitionistic logic.",
    "m.mentions": {},
    "m.relates_to": {
      "rel_type": "m.replace",
      "event_id": "$0s2AQIs-h8MDLmC0PV3Y3__1rh8-OEt6HTCsmog9bPE"
    }
  },
  "origin_server_ts": 1696689036911,
  "unsigned": {
    "age": 424032713,
    "transaction_id": "m1696689036840.22"
  },
  "event_id": "$E6aDEmxOeibNH9uOR8tq_zaR0SSYSWwbzVn4YH27gTM",
  "room_id": "!HZHMaUPzZrRUGtTihh:jaguatirica.pontofixo.net.br"
}

So, the issue seems to be related to the m.new_content property, as described in MSC2676. I can reproduce the issue with rooms versions 9 and 10.