I have, as of last Friday, been able to edit the Azure Automation runbook in MS Flow. It no longer gave the Flow Failed to fetch error, but I did need to repopulate all of the parameters that I had previously set. Anyway things seem to be running now.
Also, this only works for me in IE. In Chrome and Firefox I still get errors.
Thank you for this info. I talked to my team mate and she said the same thing, she only uses IE when working with Flows. I will see if this will work.