[BUG] Teams / Graph API Regression: "codeBlockEditor" vs <codeblock> in HTML Content Results

Start by reproducing the issue with a Teams chat message containing inline code followed by a triple-backtick block, then query it with GET /v1.0/chats/{id}/messages/{msg}. The payload names no files, tests, or SDK entry point; done would require the returned HTML to preserve each code block's own content instead of reusing an earlier code element.

Describe the bug

Per: https://learn.microsoft.com/en-us/answers/questions/5728345/(bug)-teams-graph-api-regression-codeblockeditor-v

[I'm not sure if the "Javascript SDK" is the right place for this, because it's a server-side bug, but here goes... If there's a better repository, I'd be happy to repost it there, thanks!]

Within the past week or so (January 2026) whenever I GET /v1.0/chats/{id}/messages/{msg}, it seems that "triple-backtick" code blocks have gone from being sent as <p itemtype="http://schema.skype.com/CodeBlockEditor"> elements to dedicated <codeblock> tags, with embedded <code> inside...

That wouldn't be a problem, EXCEPT I've noticed that when there's another <code> tag earlier in the message content, it replaces the contents of any subsequent <codeblock><CODE>...</CODE></codeblock> blocks.

To wit:

    The `message` is:
    ```
        Hello, world!
    ```

Produces the following snippet of JSON:

    "body": {
      "content": "<p>The <code>message</code> is:</p>\n<codeblock class=\"PlainText\"><code>message</code></codeblock>",
      "contentType": "html"
    }

Note that the second message does NOT say "Hello, world!"

This also happens for other "triple-backtick" code blocks:

    ```
    Line One
    ```

    Line `Two`

    ```
    Line Three
    ```

Becomes "One, Two, One" :-(

Expected behavior

In the first example, I would expect to see <codeblock><code> Hello, world!</code></codeblock>

How to reproduce

Send a Teams message (chat or channel) with the markup:

    This is `inline code`

    ```
    This is a block
    ```

Then query that message via the Graph API; you'll see that it returns the wrong results.

SDK Version

No response

Latest version known to work for scenario above?

No response

Known Workarounds

No response

Debug output

No response

Configuration

No response

Other information

Like I say, I tried looking for a more API-related repository, but github.com/microsoftgraph lists, like, 230 different repos, and I only made it through ~3 pages of results before I gave up... «sigh»