Notebook validation failed: 'transient' was unexpected

[gnestor]

I just started getting validation errors a couple days ago so it must be a local environment issue. When I save notebook is lab and open the same notebook in classic notebook, I get a validation errors:

Notebook validation failed: Additional properties are not allowed ('transient' was unexpected)

I tried pulling the latest and installing notebook and lab as well as nbconvert, nbformat, ipython, etc.

Any ideas?

[takluyver]

The 'transient' key is for data that's not meant to be persisted, I believe. If lab is writing notebook files with that key, I'd say that's a bug in lab.

[blink1073]

Tracking as jupyterlab/jupyterlab#1698.