Would this be connected too?
This error could be caused by required additional software packages which are missing or not installable. Furthermore there could be a conflict between software packages which are not allowed to be installed at the same time.
Transaction failed: Package dependencies cannot be resolved
The following packages have unmet dependencies:
init: systemd-timesyncd: Depends: libsystemd-shared (= 255.4-1ubuntu6) but 255.4-1ubuntu6 is to be installed
Would it be considered advisable to remove / format any current Noble installs and replace them once more is known, or is that not necessary?
The Noble archives are in a changing state and have been for a while with the time_t transition. Now they’re in a similar—if not worse—state with a security bug whose impact is not fully understood. Personally, I’d avoid using any Noble installs right now. When everything is well known and the archive is in a manageable state, and ISOs start building again, then I would make a new install and carry on like normal.
The one thing I’d absolutely advise: don’t use Noble in production right now.
Moderator Note:
This topic is for sharing constructive information about the problem, status of solutions, and relevant questions and discussion. Questions to help folks understand are on-topic and welcome.
This is not a topic for general complaints. Off-topic items will be removed to keep this conversation on-topic.
Folks who are frustrated that Noble isos aren’t working for them today: Please understand that everybody already knows, and that everybody already agrees with you.
Thank you for your understanding.
So, atm all the proposed up-to-date packages are being updated too.
I appreciate all the effort being done to ensure things are done correctly instead of done quickly. I’ll happily wait for all this work to complete considering the XZ issues.
Yes, thanks to this huge effort this weekend.
Nobody has said that Beta Freeze won’t be today, so it seems like it is. 
And what about missing many amd64 packages.
For example if you look at libarchive13, libarchive-dev and libarchive-tools packages in Noble they all have: arm64 armhf i386 ppc64el riscv64 s390x and no amd64.
https://packages.ubuntu.com/search?keywords=libarchive&searchon=names&suite=all§ion=all
Also as you can see the other Ubuntu versions do have the amd64 architecture packages.
Another example is Lomiri Operating Environment packages:
https://packages.ubuntu.com/search?suite=all§ion=all&arch=any&keywords=lomiri&searchon=names
Another one aptitude:
https://packages.ubuntu.com/search?suite=all§ion=all&arch=any&keywords=aptitude&searchon=names
Do all of those are related to the time_t transition or is it some other problem.
Long story short: this is expected. The Noble repos are in flux for multiple reasons as mentioned above.
As stated in the IRC snippet by vorlon quoted earlier in this thread, amd64 binaries built when the affected xz-utills was in -proposed have been deleted. These will be replaced by doing rebuilds of those packages, which is in progress but not yet complete.
This snipped from the latest update on the xz security issue should hopefully give a more clear indication of the massive overhaul that is happening in the Noble repos right now:
New here. Joined after finding this post when I set out to see why the upgrade included so many i386 packages instead of amd64 ones. Seems like I’ll have to wait for a while now.
I discovered it yesterday when I decided I wanted to install 24.04 and try it out, but I couldn’t install anything I actually use (GIMP, libreoffice, etc etc etc). I came on this thread as the problem for all the missing packages and broken dependencies.
I’m sure that rebuilds are well underway, my question is will this delay the release on 4/25?
You may have saw the Beta was delayed by a week:
This is reflected on the official release schedule:
as well as this event that was made for it:
but you’ll notice that the final release date hasn’t changed, either in the official release schedule or the event created for it:
tl;dr no
This hosed my entire system. Thank goodness for timeshift. I reverted back to 22.04 to find mutter was broken. Ubuntu seems to be in a bad place.
Don’t 
use development releases in production
There’s a newer version of Mutter in jammy-updates than in jammy-release, so if you reverted but didn’t upgrade, that might be the explanation.
You could also upgrade to 23.10.
No, hence the reason we have tools like Timeshift, and Clonezilla. A development box is not a production machine.
Words are hard, and they have multiple meanings.
A development machine is absolutely a production machine.
As in, you have it in production use, for development.
The development release is and and always has been unstable, and not recommended for anyone to use other than those contributing to Ubuntu, and testing Ubuntu.
Also, coming here to tell us you had to restore an important (to you) system from backup is a fantastic story to tell 
. Please tell more people to have backups of their important systems. Even if they install the wrong release on it 