Going in and out of sleep mode should not bring you to the sign in page.
Your taking some kind of error that is causing a reboot.
When's the last time you gave the innards a good cleaning?
I love the sleep feature . It worked fine for years. I never HAD to shut down OR boot up unless I wanted to.
Now, however, it, ghost-like, shuts down and reboots to the sign in and sits there waiting for my password.
How can I get back to the sleep feature.