Due to an issue in ext4 with data corruption in kernel 6.1.64-1, we are pausing the 12.3 image release for today while we attend to fixes. Please do not update any systems at this time, we urge caution for users with UnattendedUpgrades configured. Please see bug# 1057843: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1057843
This was already fixed in 6.1.66. Both are "old" kernels, so it's nothing to worry about, unless you/your distro was deliberately staying on 6.1 for some odd reason (yes, I'm aware 6.1 is LTS, but so is 6.6).