[Risolto] Translation from German to Italian disappears after a few days of completed translation

Background of the issue:
We have noticed that as soon as we have finished translating pages from German to Italian, after a few days they only exist in German and the Italian has disappeared. This only happens on the pages, but not in the listings or posts. The site we need help with is link nascosto.

Symptoms:
Translation from German to Italian disappears after a few days of completed translation.

Questions:
Why do the Italian translations of our pages disappear after a few days?
Why does this issue only affect pages and not listings or posts?
How can we prevent the Italian translations from disappearing?