The Intune-managed CoreImage is configured to permit more than one signed in user.  This is called Fast User Switching (FUS).

In the following screenshot, you can see that User 1 (Coretest1) is the active user while User 2 (Coretest5) is also logged in.  User 1 logged in while User 2 was already logged in.  FUS permits User 2 to remain signed in--though only in the background in a "disconnected" state--while User 1 becomes the active user.

Caveats:

1. FUS does not permit a remote desktop connection while a user is signed into the device.  Windows 10 permits multiple local logins with FUS, but only a single remote desktop session with no other local users concurrently signed in.
2. Each user session consumes device resources such as memory (RAM) and processing (CPU).  This means performance will be significantly impacted using FUS.  Only use FUS when absolutely required and performance expectations are aligned.

With Fast User Switching, or FUS, enabled, you will see the last user who signed in when you turn on the device.  This may be you (which we'll refer to as User 1 in this article), simplifying your sign in experience by only requiring you to enter your password.

However, this may not be you.  In that case, (1) click on Other user in the lower left-hand of the screen and (2) enter your uniqname and UMICH password to sign in and start your Windows session.

If you (User 1) have locked the screen and User 2 wants to sign in, User 2 should (1) click Other user and (2) enter their uniqname and UMICH password as they would if the last signed in user was someone else as shown previously.

If you want to permit someone else (User 2) to sign in while you (User 1) are in your active Windows session, you can click Switch user in your session's start menu to return to Windows' sign in screen.

As shown previously, they (User 2) can click Other user and enter their uniqname and UMICH password to start their own Windows session.  This will put your (User 1's) session into a "disconnected" state but leaves you signed in.

Once User 2 is signed in while you (User 1) remain signed in--now with in a disconnected session--FUS allows one to switch back and forth between the signed in sessions using the start menu.

In the case where User 2 selected your (User 1's) session in their start menu to switch back to it (shown in the previous screenshot), Windows will return to its sign in screen where you (User 1) can (1) select your account from the list of users and enter your password to return to your session--now leaving User 2's session in a disconnected state (shown below).

You (User 1) may choose to Sign out which will end your Windows session and return you to Windows' sign in screen.

Once User 2 signs back into Windows and becomes the active user, they will see that you no longer have a Windows session as shown below.

Note that you cannot tell if another user is signed in on the sign in screen.  However, if you do attempt to shut down or restart the computer, Windows will tell you that another user is signed in and they may lose unsaved work.  You do not need to be an administrator to shut down or restart the device while someone else is signed in.