Updates fail after switching to 4.2

I did the in-place upgrade to Qubes 4.2 and all my app Qubes are working well by now. However, I now see the notification that there are some updates to several app qubes. But clicking on Update starts the process and gives me the following error for every single app qube (except for the debian-12 template which I selected individually and then it worked).

Updating Z-brave
Refreshing package info
Refreshing packages.
Fail to refresh InRelease: https://deb.qubes-os.org/r4.2/vm bookworm InRelease from https://deb.qubes-os.org/r4.2/vm/dists/bookworm/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian bookworm InRelease from https://deb.debian.org/debian/dists/bookworm/InRelease
Fail to refresh InRelease: https://brave-browser-apt-release.s3.brave.com stable InRelease from https://brave-browser-apt-release.s3.brave.com/dists/stable/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian-security bookworm-security InRelease from https://deb.debian.org/debian-security/dists/bookworm-security/InRelease
Fail to refresh InRelease: https://deb.qubes-os.org/r4.2/vm bookworm InRelease from https://deb.qubes-os.org/r4.2/vm/dists/bookworm/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian bookworm InRelease from https://deb.debian.org/debian/dists/bookworm/InRelease
Fail to refresh InRelease: https://brave-browser-apt-release.s3.brave.com stable InRelease from https://brave-browser-apt-release.s3.brave.com/dists/stable/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian-security bookworm-security InRelease from https://deb.debian.org/debian-security/dists/bookworm-security/InRelease
Fail to refresh InRelease: https://deb.qubes-os.org/r4.2/vm bookworm InRelease from https://deb.qubes-os.org/r4.2/vm/dists/bookworm/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian bookworm InRelease from https://deb.debian.org/debian/dists/bookworm/InRelease
Fail to refresh InRelease: https://brave-browser-apt-release.s3.brave.com stable InRelease from https://brave-browser-apt-release.s3.brave.com/dists/stable/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian-security bookworm-security InRelease from https://deb.debian.org/debian-security/dists/bookworm-security/InRelease
Fail to refresh InRelease: https://deb.qubes-os.org/r4.2/vm bookworm InRelease from https://deb.qubes-os.org/r4.2/vm/dists/bookworm/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian bookworm InRelease from https://deb.debian.org/debian/dists/bookworm/InRelease
Fail to refresh InRelease: https://brave-browser-apt-release.s3.brave.com stable InRelease from https://brave-browser-apt-release.s3.brave.com/dists/stable/InRelease
Fail to refresh InRelease: https://deb.debian.org/debian-security bookworm-security InRelease from https://deb.debian.org/debian-security/dists/bookworm-security/InRelease
Refreshed.
E:Failed to fetch https://deb.debian.org/debian/dists/bookworm/InRelease  Reading from proxy failed - read (115: Operation now in progress) [IP: 127.0.0.1 8082], E:Failed to fetch https://deb.debian.org/debian-security/dists/bookworm-security/InRelease  Reading from proxy failed - read (115: Operation now in progress) [IP: 127.0.0.1 8082], E:Failed to fetch https://brave-browser-apt-release.s3.brave.com/dists/stable/InRelease  Reading from proxy failed - read (115: Operation now in progress) [IP: 127.0.0.1 8082], E:Failed to fetch https://deb.qubes-os.org/r4.2/vm/dists/bookworm/InRelease  Reading from proxy failed - read (115: Operation now in progress) [IP: 127.0.0.1 8082], E:Some index files failed to download. They have been ignored, or old ones used instead.

I have tried restarting my PC already and I am generally online.

Did you mean for every single template qube and not app qube?
Is Z-brave a template qube?

Do you have the same update proxy qube for your debian-12 template and templates that fail to update e.g. Z-brave?
What’s the template of your update proxy qube used for template updates?

After another reboot this fixed itself. No idea what was the root cause. Possibly somehow connected to me upgrading the debian-12 template and then rebooting.

Did you mean for every single template qube and not app qube?

Correct, I meant for the template qube.

Is Z-brave a template qube?

Exactly.

Do you have the same update proxy qube for your debian-12 template and templates that fail to update e.g. Z-brave ?

I do not know what an update proxy qube is but I basically just followed the instructions of in-place upgrade.