The suggested workaround for now is to open a separate tab/window in safe mode (add /safe to the end of the notebook URL). The notebook will update simultaneously in all open editor instances (provided your internet connection remains stable).
I just wanted to chime in to say that with Broadcast Channels:
You also have a pretty easy way to synchronize local state between the same notebook open in multiple tabs or windows. It makes it even easier to edit a notebook and tweak sliders in one place, while keeping the output consistent and never needing to refresh…