I'm currently running Ubuntu Studio 21.10 on a 2019 Dell desktop. I upgraded Ubuntu Studio from 21.04 to 21.10 using the command line. I have a login screen that I created after modifying an Ubuntu Studio login screen. I have a 5 second timeout for the BIOS and for the grub screen. Logins were fine until about 2 weeks ago, when I found that the boot would proceed apparently normally (with the BIOS and grub timeouts) and the login screen would appear, then disappear after about 3 to 5 seconds. Typing my login password did not prevent the screen from disappearing, and continuing to type my password did not log me in. If I hard restart my computer (since there was no way that I could see to restart it otherwise), the login screen would not disappear. I am using the Ubuntu Studio sddm as a display manager. I've searched both Ask Ubuntu and the internet, and did not really find any solutions.