[Neos] Missing language switcher and errors in the Neos admin after upgrade from Neos 1.1 to Neos 1.2

[Pavlina Drosos]

Hi guys,

I have recently upgraded two sites from Neos 1.1 to Neos 1.2, following
these instructions:
http://neos.typo3.org/develop/download/upgrade-instructions-1-2.html

The first of them seems to work and in the Neos admin a language switcher
with different languages appeared. But in the second site the language
switcher is missing. Also when trying to move a page in the tree and apply
the changes I see errors in the admin, like this:
http://postimg.org/image/mhhpepvxh/

I have noticed that for the first site when executing

./flow node:repair

additional content elements were created for all languages. For the second
site this didn't happened.

The main difference between the two installations is that in the second one
Neos is used for multiple sites (domains). Locally I have a single site,
the language switcher is there and the admin works, but on our test server
multiple sites are set-up, the language switcher is missing and errors
appear in the Neos admin.

Do you have an idea how can I fix the multi-site installation?

Thanks in advance!

KR,
Pavlina