send eloquent collection for proper serializationg

src/Illuminate/Notifications/ChannelManager.php

@@ -114,7 +114,7 @@ protected function queueNotification($notifiables, $notification)
         foreach ($notifiables as $notifiable) {
             foreach ($notification->via($notifiable) as $channel) {
                 $bus->dispatch(
-                    (new SendQueuedNotifications([$notifiable], $notification, [$channel]))
+                    (new SendQueuedNotifications($this->formatNotifiables($notifiable), $notification, [$channel]))
                             ->onConnection($notification->connection)
                             ->onQueue($notification->queue)
                             ->delay($notification->delay)