[Risolto] After creating the Italian translation, I can't modify it because only parts of the page appears

Background of the issue:
I was trying to update the Italian translation on our main page. The issue can be seen at link nascosto.

Symptoms:
After creating the Italian translation, I can't modify it because only parts of the page appear. The sections I could easily modify earlier have disappeared, and the text is still in English.

Questions:
Why can't I modify the Italian translation?
Why have the sections disappeared and the text remains in English?...