I got that a few times already and it always goes away after a few minutes/hours. I don't know if this is during some updates or something or if we should be worried but it happened several times to me too.
Based on the time of your post, my guess is that you received this during our maintenance window. If you (or eethan), see it again, please note the time and post the time. It isn't surprising that this is happening during the maintenance windows but would be an issue if it was happening any other time.