If something is causing Live Update to not complete satisfactorily (such as antivirus/firewall block), doesn't it seem reasonable that it would help if an error log was created saying as much? Then we wouldn't be speculating that it MIGHT be related to AV/firewall block?
Of course it's possible to create a log and, this is not even always required because, the latest Live Update (since GSX L2), as soon as it downloads a file, it will verify its hash and will compare it against the server, to be sure nothing is "blocking" the download. And will give you an alert about it.
OF COURSE, if your antivirus has even blocked the Live Update *itself*, such function wasn't available in the old Live Update.
But the issue is, if you installed the new JFK 2 and the new GSX, they already CONTAIN the new Live Update so, it's really not possible something like you are describing. The only possible (highly unlikely) chance for this to be happening, is that your local Cloudflare node, which caches all our Live Update files, still hasn't been updated with the new files we posted yesterday.
It's very unlikely, but it's theoretically possible, and it's the only explanation compatible with your report, also considering NOBODY else has posted the same error at JFK2 so, if we really had the old version online (we don't), every single JFK2 user would have seen the same error, not just you.
You might also try this, remove this folder:
%APPDATA%\Virtuali\UpdateCache
Then run Live Update again. That's another folder that a firewall/antivirus might mess up with.