Symptoms
The SleepAgentServer process may consume 30–100 percent of available CPU time on Microsoft System Center Configuration Manager current branch clients that are running on Windows 10-based computers that have the May 2019 version 1903 update installed.
Multiple entries that resemble the following are recorded in the Sleepagent.log file:
Ignoring heartbeat for new machine {client} with expired DHCP lease 11/23/1981 09:23:50 5/17/2019 9:33:18 AM
Ignoring heartbeat for new machine {client} with expired DHCP lease 11/23/1981 09:23:50 5/17/2019 9:33:18 AM
Ignoring heartbeat for new machine {client} with expired DHCP lease 11/23/1981 09:23:50 5/17/2019 9:33:18 AM
Ignoring heartbeat for new machine {client} with expired DHCP lease 11/23/1981 09:23:50 5/17/2019 9:33:18 AM
Cause
This issue occurs because of DHCP data storage changes that were made in the May 2019 Windows 10 update.
Workaround
To work around this issue, set Enable wake-up proxy to No in the client settings.
Status
An update for Windows 10 is in development to resolve this issue. This article will be revised when the update is available.
References
Plan how to wake up clients in System Center Configuration Manager
See the "Power management" section of About client settings in Configuration Manager