It doesn't make much sense to me when there's a service running idle as a package installer (namely
If you update manually then it can be removed from autostart. See: Disable gnome-software from loading at startup
It sparked my interest when I inspected my dnsmasq log and found all of the package repository servers being resolved once a day. This would occur immediately after an internet connection was established.
I thought I had put an end to all auto-update features but I missed this one. The Ubuntu Documentation for Automatic Connections applies only to 14.04 LTS too which didn't help me (running 16.04).