From what I understand Autosave is disabled whilst recording/playing back. Recording I understand, but unless working with a slow PC, I can’t see any need to disable autosave whilst playing back: and if you work in cycle mode whilst mixing as I do, you can find that the project hasn’t been autosaved in a long time, because you never actually press stop !!
So please give us an option in Preferences to allow autosave whilst playing back.