Interesting and most likely true
I see it as the usual game of the west. Let's play it out.
First of all, again and again there is a "Chinese official" that is so higher up in Xi's circle who is also close friend of Financial Times/West. So convenient for the west to claim anything and everything. It also demonstrate that the Chinese security is like French cheese.
Now, if Putin warned Xi before the invasion, this "Chinese official" would leak this information then or now to the west who will conveniently blame China being the conspirator of invasion, defeating China's neutrality.
On the other hand, if Putin did not warn Xi, this "Chinese official" would leak it then or now to the west who will conveniently make China looks stupid and not protecting Chinese lives.
Don't you see it? No matter the truth, the west always win, China is always bad, Russia is always bad. From a Chinese stand point, agreeing with the west and blaming Russia will ONLY benefit the west, nobody else.
Besides, any national leader will NOT warn or evacuate any of their citizens in the war zone before a surprise attack. Otherwise you warn the enemy. Russia would NOT have warned their own citizens in Ukraine. Nor would China warn Chinese citizens before invasion of an enemy country. Think about PLA's invasion of Taiwan, what would you expect? So I don't see anything surprising.
My advice to oversea Chinese citizens, keep your eyes open, leave on your own judgement, don't wait for the embassy to tell you before hand.