bug across OS : Failed to save 'myfile.http': t.getCells is not a function

[JLT032]

whenever a file is save it returns this message

Failed to save 'myfile.http': t.getCells is not a function

[AnWeber]

@commandline-be I need some more information. The error does not occur for me. Neither in vscode nor vscodium. I edited an existing and created a new file from scratch. No Error

[AnWeber]

In latest Insiders this bug occurs

[AnWeber]

I added a typeguard till vscode team discusses what to do. There is a minor API Change which breaks my code. NotebookData is not always a class but my extension is handed over a object with same interface