As configurações que você está mostrando são para a (s) varredura (s) programada (s), não para a varredura ociosa na qual você está vendo o pop-up.
De acordo com a Symantec aqui , pode utilizar o" Slient Mode "para silenciar os pop-ups de Idle-Scan durante uma duração selecionada de tempo.
To turn on Silent Mode from the Settings window
In the Norton Internet Security main window, click Settings.
In the Settings window, click the General tab.
In the left pane, click Silent Mode Settings.
In the Silent Mode row, move the On/Off switch to the left to the On position.
In the Settings window, click Apply.
In the Turn on Silent Mode dialog box, in the Select the duration drop-down list, select how long you want to turn on Silent Mode, and then click OK.
In the Settings window, click OK.
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To turn on Silent Mode from the notification area
In the notification area on the Windows taskbar, right-click the Norton Internet Security icon, and then click Turn on Silent Mode.
In the Turn on Silent Mode dialog box, in the Select the duration drop-down list, select how long you want to turn on Silent Mode, and then click OK.