I am also affected by this using Fedora Silverblue 33. Family members are a bit annoyed by this
I tried looking for workarounds. The two things I found didn’t work.
$ cat /etc/rpm-ostreed.conf
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# For option meanings, see rpm-ostreed.conf(5).
but as you see AutomaticUpdatePolicy is set to none, which means don’t update, by default.
The second is unchecking Automatic Updates and notifications from Gnome Software’s update preferences. However this doesn’t appear to be respected. Gnome Software still looks for updates without being asked. Incidentally this is annoying because it interferes with my manual commands to check for updates, only one refresh-md can run at a time. I also checked with dconf-editor and download-updates is set to false but the bug is still here.
Anyone can think of any other workaround till the bug is addressed?