WP4.0 auto-upgrade downloading wrong file?

I have a local install of WP3.9.2 and I am trying to update it to WP4.0.

When I click on the update button it downloads the file:

https://downloads.www.ads-software.com/release/wordpress-4.0-no-content.zip

…this breaks wordpress as then no pages display even in twentyfourteen template.

However, I completely reset the local WP install (losing all my customized site) and then ran the upgrader again. This time it downloads:

https://www.ads-software.com/wordpress-4.0-new-bundled.zip

Which works!!!

So my question is, what is the ‘logic’ behind what zip file it downloads? If I know that then maybe I can identify what the issue is with ‘my’ site.

Thanks,

Alex