@DS
As YoussefSaad mentioned, The number of times the user can snooze reboot notification populated from Software Center depends on the "Computer Restart" client setting. We may calculate the limitation on the number of times a user can snooze through "amount of time after the deadline", "final countdown notification" and "frequency of restart reminder notification". After the deadline, If we select "snooze", another temporary notification will be displayed after the snooze time has passed. This behavior has not reached the final countdown. We chose to snooze again, and the snooze interval is one hour, then Software Center notifies the user again in 60 minutes. When it reaches the final countdown, Software Center shows the user a notification they can't close. The progress bar is in red and the user can't Snooze it. Like below screenshot:
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