ChromeOS version: 67.0.3396.99 (the customer has confirmed that it can be reproduced the issue with Beta and developer mode. )
(Locally tested:67.0.3396.99 , 64.0.3282.190)
ChromeOS device model: eve
(Local test device:Swanky, veyron-minnie,
Case#: 16446765

Description: SAMLOfflineSigninTimeLimit Policy: not always prompted to do an external authenticated login, even if it's been over 24 hours since the last online authentication.

User information and local test info.
https://drive.google.com/open?id=1NvXmWKL_IPjdq9RG7reC3UF1LJKRzL8cCHBmeJFsvxY

Steps to reproduce: 
-The customer reported.
SAMLOfflineSigninTimeLimit Policy is set to 24 hours. 
0. Perform an authenticated sign-in and use chromebook normally. Do not shut down. Instead put to sleep. 
1. After 24 hours have elapsed, wake the chromebook from sleep and sign-in 
(no online auth required since the user is still signed-in) 
2. After signing-in, click user icon on the shelf -> Shut down 
3. Wait approx. 15 seconds and turn the computer back on 
4. At the login page, notice that the 'Sign Out' button is not there, 
indicating that the user is signed-out. However, online auth is not being 
required and the user can sign-in normally. 
5. After signing-in, immediately shut-down the machine again 
6. Wait approx. 15 seconds again and turn the computer back on 
7. This time, online auth is now required. 
8. In short, it seems that an immediate shutdown after wake from sleep doesn't enforce the policy but a subsequent shutdown does. Lastly, is there a 
chrome:// page that we could check to verify when the last time an authenticated sign-in occurred on a machine was? 

Current Behavior / Reproduction:  the online sign-in window does not appear after comes back from the sleep mode & initial reboot even if it's been over 24 hours since the last online authentication.

Expected Behavior: the online sign-in window should always appear after retune back from sleep mode & initial reboot after the sleep mode if it's been over 24 hours since the last online authentication.

Drive link to logs: 
Version info:https://drive.google.com/open?id=1GPW9-va1SEGmTUuRob9B3wPN2cJElLTQ

Additional info from the customer.
1) When using the sing out, the behavior works as expected. they are required to authenticate. 
2) Customer has shared the following videos 
2.1) When shutting down, This was reproduced at 2:22pm PDT 07/31/2018. 
https://drive.google.com/open?id=1LbFcVrHcIA3Yuj5XcOGl0SVfKLhnXHJQ
2.2) when signing out instead (working as expected)***This was reproduced on 8/2/2018 at 4:34 pm PDT
https://drive.google.com/open?id=1zWBcQZ_0gTMl-ZoVzKKOHc_C7nwDg4SJ
2.3) workaround to bypass the authentication.
https://drive.google.com/file/d/1JFA3SLxgNLEAZbupqXCR8RR2y14SWxbO/view
3) debug logs collected.
https://drive.google.com/open?id=1NARf1IFqyavh2emDmGmLx8X-gtMawVWs