For me, it is important to know if you receive this notification just once or if it repeats. Updater check for new updates of Turris OS every 4 hours.
I see that you received it one hour after midnight, couldn’t there be a possibility that there was a short outage or planned maintenance by your ISP, which results in temporary downtime of your Internet connection?
If you don’t receive the notification today or now, I would say it is just fine.