Our product is affected by this bug. It isn't that the content of the textarea is saved with the autofill so then replaces the content. The content stays as the value in the box but the value gets truncated and the textarea element no longer functions correctly. Autocomplete="off" on the textarea does not resolve the issue.
I have posted the report that I found when trying to figure out what the heck was going on. However, I have reported the issue through the Microsoft Edge feedback tool with my own example.
