I'm not sure what you mean by auto-login not working. I've had my Steam account for 11 years and I can remember a time where that was the case, but it works so reliably nowadays I didn't even remember it was an issue until reading your comment.
My experience is that a lot of this stuff works really well if you're using Steam regularly, and completely falls apart if you use it once a month.
It has to be a bug, or maybe a security feature for accounts of a certain size?