Canonical has implemented a staged roll-out for some Ubuntu package updates.
I find that rather annoying at times, e.g. when preparing the laptop for traveling.
So for my memory and for the benefit of others:
sudo apt -o "APT::Get::Always-Include-Phased-Updates=true" dist-upgrade
This can - for permanent use - be put into a config file, e.g. Gerrit Heim puts it into /etc/apt/apt.conf.d/99-Phased-Updates [German]. Some other options around this staged roll-out feature are "documented" on a thread in the Ubuntu discourse forum.