Formatting creates extra newlines

[WIPocket]

Steps to reproduce

Send texts containing formatting

Outcome

What did you expect?

Same functionality as old version of Element Android and other clients.
Element Desktop 1.11.23:

What happened instead?

Most formatting options start a new line.

This seems to only be the case when it is the first formatted text in a paragraph:

With the markdown:

one _two_ three

four _five_ six

Your phone model

Google Pixel 7

Operating system version

GrapheneOS stable / Android 13

Application version and app store

Version 1.5.25 [40105250] (F-f74a885a), Matrix SDK Version 1.5.25 (f74a885), olm version 3.2.12, from F-Droid

Homeserver

Synapse 1.77.0

Will you send logs?

No

Are you willing to provide a PR?

No

[Florian14]

It seems not but can you confirm that you're not using the new rich text editor? @jonnyandrew, do you have any changes in mind with the new composer that could have caused a regression on this part?

[WIPocket]

I was not using the new rich text editor. Toggling "Enable rich text editor" or "Enable LaTeX mathematics" does not change the rendering of these messages.

It renders wrong regardless of what client I send the message from, be it this new version of Element Android, Element Desktop or gomuks.

The event source looks like this:

{
  "room_id": "<redacted>",
  "type": "m.room.message",
  "content": {
    "msgtype": "m.text",
    "body": "this _is_ underscores",
    "format": "org.matrix.custom.html",
    "formatted_body": "this <em>is</em> underscores"
  }
}

[jonnyandrew]

It could be caused by #8011 which attempted to work around the following (seemingly related) issue:

• Inline code formatted messages display with extra line breaks #7975
• Extra new lines inserted in front of HTML inline code noties/Markwon#423