Hi Niccolo, you might want to check out this thread — it's getting long but it's ongoing and I think it's the same symptom you're describing.
Have you been in the habit of creating a release after a good stopping point? One mitigation might be to release more often, even if they're just draft releases and not ready for publishing.
Auto-saving may still be an issue, but you might lose, say, only 10 minutes of work versus whole days' worth.