I am trying to setup a Kiosk account running a sideloaded app. This worked by using the "Assigned Access" mode before version 1803. Version 1803 broke it, and the kiosk user was immediately logged out when trying to login, without showing the app. Since version 1809 "Assigned Access" seems to have been renamed "Kiosk Mode".
Some devices now only kick me out the first time I login (after a reboot). After that the user is logged in and stays logged in, showing the app until you exit it with Ctrl+Alt+Del.
Sadly this still fails on some other machines, where you are always logged out immediately.
The kiosk account is a local account which is not an admin. It can be set as kiosk account without problem. But once I try logging in to it, I am immediately kicked out again, to the lock screen.
What is the reason for this auto-logout, and how can I fix it?