I had the same issue. I did not want to reinstall with internet. I hope this is the only issue caued by that.
Here is how I solved it:
Code:
sudo -s
export KEYRING=/etc/apt/trusted.gpg.d/science_EtherLab.gpg
curl -fsSL https://download.opensuse.org/repositories/science:/EtherLab/Debian_12/Release.key | gpg --dearmor | sudo tee "$KEYRING" >/dev/null
apt update
By just overwriting the signature with the latest.
