Non conoscendo come hai configura, l'app che utilizzi etc. è difficile aiutarti
https://learn.microsoft.com/en-us/windows/configuration/assigned-access/configure-multi-app-kiosk?tabs=intune
Sign out of assigned access
By default, to exit the kiosk experience, press Ctrl + Alt + Del. The kiosk app exits automatically. If you sign in again as the Assigned Access account, or wait for the sign in screen time-out, the kiosk app relaunches. The default time-out is 30 seconds, but you can change the time-out with the registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Authentication\LogonUI
To change the default time for Assigned Access to resume, add IdleTimeOut (DWORD) and enter the value data as milliseconds in hexadecimal.