When GNOME-Software finds new system updates, the "restart & install" feature doesn't work anymore. This is the case for PureOS as well as for Debian Buster.
When clicking on "restart & install" the computer restarts but doesn't install anything. Instead, it restarts again straight away. The updates are still visible and only installable through the command line (which is blocking the average user from being able to update his system).
Sorry in advance as I know that this should be a Debian bug but I have some difficulties sending bugs on the Debian tracker and I know that @mak is the right person for this bug on both distributions! :)