Native Notebooks - Changing kernel causes markdown to flicker, then disappear

[claudiaregio]

• VS Code Version: 1.57.0 & 1.57.0-insider

Steps to Reproduce:

1. Open notebook
2. Change kernel - markdown will flicker
3. Change kernel again - markdown disappears
4. This behavior continues every other kernel switch

[rebornix]

The way I reproduced this issue is

• create a code cell
• change it markdown
• double click to edit
• escape
• the markdown cell is blank

notebookWebviewPreloads.js:3 Uncaught (in promise) Error: Could not find renderer
    at Object.render (notebookWebviewPreloads.js:3)
    at K.updateContentAndRender (notebookWebviewPreloads.js:3)
    at new K (notebookWebviewPreloads.js:3)
    at Object.createMarkupCell (notebookWebviewPreloads.js:3)
    at notebookWebviewPreloads.js:3
    at Array.map (<anonymous>)
    at Object.ensureMarkupCells (notebookWebviewPreloads.js:3)
    at notebookWebviewPreloads.js:3

[vscode-triage-bot]

Pinging notebook topic followers: @claudiaregio @rchiodo @greazer @DonJayamanne @jilljac @IanMatthewHuff

[rebornix]

#126056 (comment) is different from the original issue, extracted to #126069

[mjbvz]

@connor4312 I suspect this may be from 7c226ae (or related followup changes) but am still debugging. Any ideas off the top of your head?