Microsoft now has some explanation to why Windows 10 version 1809 users are facing approximately 60 seconds delay in system sleep or shutdown process. According to Microsoft, a bug in the implementation of USB Type-C Connector System Software Interface (UCSI) in Windows 10 version 1809 could be responsible for the slowdown in system sleep or shutdown. The company has confirmed that the problem occurs when power-down occurs while UCSI software is handling plugged/unplugged event on a USB Type-C port. However, the bug does not affect standard USB Type-C functionality on your Windows 10 machine.
Explaining the issue, Microsoft's Philip Froese had this to say in his post on Microsoft USB Blog:
"A bug in the USB Type-C Connector System Software Interface (UCSI) software implementation in Windows 10, version 1809 can cause a 60 second delay in the system sleep or shutdown process if the power-down happens while the UCSI software is busy handling a new connect or disconnect event on a USB Type-C port. Apart from the extra one minute, the sleep or shutdown process takes in this circumstance, this bug does not affect normal functionality of USB Type-C on your machine. The system and the USB Type-C ports should continue to function properly after the next wake or restart of the system."
If you happen to run Windows 10 version 1809 on your machine, you might have noticed this issue already. However, at the time of publishing this story, Microsoft has not listed this bug as 'Known Issues' in Windows 10 version 1809. Earlier, another issue was discovered where devices had issues connecting to some Storage Area Network (SAN) devices using Internet Small Computer System Interface (iSCSI) after installing KB4497934. Some users also reported seeing an error in the System log section of Event Viewer with Event ID 43 from iScsiPrt and a description of “Target failed to respond in time for a login request.”
Microsoft is currently investigating the issue with connecting to SAN devices in Windows 10 version 1809.