The feeling of being "on autopilot" when doing a task has to do with your, let's call it, supervisory process being otherwise occupied. It doesn't suggest that

The feeling of being "on autopilot" when doing a task has to do with your, let's call it, supervisory process being otherwise occupied. It doesn't suggest that that the other mental processes which are responsible for figuring out the actions have changed their character or mode of operation. "You" are just not paying attention to it in that moment.