Sorry for the long time, the rescan took a few days.
Now the balance result is correct, and only the dates on the last transaction do not match.
On bitcoin-qt it is the one of a few days ago, while on the blockchain there is (obviously) the correct one.

In my opinion what happened is this: the software skipped (I don't know why) the last 2 transactions giving me a wrong balance.

This is the hash of the last transaction that show the empty wallet
c637fc1382a5bf8350bd6422b389d5361daca72a6575bf278e4a563a988fc290