To all Italians living abroad: it's much easier to get the Chinese visa in Italy, consider coming back to Italy for 5-6 days to do the visa rather than doing it in your country of residence.
The whole story is here: https://www.lonelyplanet.com/thorntree/forums/asia-north-east-asia/china/has-anybody-heard-of-a-l-chinese-visa-expiring-less-than-three-months-after-issue-date?page=2#post_22535473
Hope this helps