I recently installed 18.10 on an old 4th gen Core i5 desktop and I'm seeing a peculiar issue with the sleep/wake behaviour. The computer sleeps normally, but everytime I wake it, the screen isn't the login window, rather it is, what I can only assume is a screenshot of when I put the computer to sleep. I cant' interact with it, it's just a frozen screen.
I found this question from a long time back, and tried the trick in there, press Ctrl + Alt + F1, and it works everytime.
I've decided to try out Ubuntu/Linux after a long macOS hiatus and so I'm not sure if the response to that question, reconfiguring the desktop manager is the correct answer. I have searched syslog for any intuitive errors, but didn't find anything. Hoping someone here has run into a similar issue and can help out.