Download https://github.com/joomla/joomla-cms/archive/3.7.x.zip
Install. Choose Extra Steps: Install Languages.
It just does not work, the page is reloaded.
[20-Aug-2016 09:05:55 UTC] PHP Notice: Trying to get property of non-object in ROOT/installation/model/languages.php on line 234

If I still click Next without languages being install, I get an invalid token
The most recent request was denied because it contained an invalid security token. Please refresh the page and try again.

this corresponds to
$package_url = trim($update->get('downloadurl', false)->_data);

Exchanging the file from the one in staging (3.6.3-dev) where installing works OK has no effect.

Then I tested skipping installing languages and went own installing.
I tried to install languages from Extensions->InstallLanguages
I got a message:

The installer can't get the URL to the remote French language. Try again later or contact the language team coordinator
The installer can't get the URL to the remote Italian language. Try again later or contact the language team coordinator

This for the same languages I installed correctly using staging.