Hello, I am also experiencing the same problem and can consistently reproduce it on both my laptop and desktop, which are both running Debian Stretch.
I was able to reproduce a similar problem (x11 crashes instead of no input) in a qemu virtual machine, but for some reason it's not crashing anymore. How can I disable using libpam-systemd? I tried installing xserver-xorg-legacy, but it didn't change anything. Best regards, Matthew