Our ServiceNow group is planning to upgrade to Tokyo release soon. We're doing the Integration testing in the Test environment right now. It appears when a device is set to anything other than the "Installed" state, the device "Is in Maintenance" field under the "USM Notebook" did not switch from false to true.
Release : 4.2
Customer removed the ServiceNow connector and let it retrieving all items from fresh.
This resolved the problem but officially the ServiceNow connector 4.6.1 is not certified for Tokyo.