Hello there,
Is the restart happening only due to updates ? Can you check if all the restarted devices have the update installed ?
After an update is installed, Windows attempts automatic restart outside of active hours. If the restart does not succeed after seven days (by default), the user will see a notification that restart is required. You can use the Specify deadline before auto-restart for update installation policy to change the delay from seven days to any number of days between two and 14.
Manage device restarts after updates https://learn.microsoft.com/en-us/windows/deployment/update/waas-restart
Hope this resolves your Query !!
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