It’s no different from what they announced.
They mentioned ‘real time’ in the update note this time.
That is, time in the real world.
The wording in the Korean update note is more accurate. The staff at Blizzard Korea translated ‘real time’ as ‘현실 시간’. (The pronunciation is 현 hyeon 실 sil 시 si 간 gan 
) In Korean, ‘현실’ means reality, real-life, and ‘시간’ means time.
I didn’t know exactly what ‘real time’ in the English update note meant, but after seeing the Korean update note, I knew they had already announced the exact time in advance.
They have been changing the definition of the event so stingy through several trials and errors (repeating several winds of fortune events).
If they define ‘24 hours’ and ‘double’ like that, then that’s it.
And we get what we don’t have originally.
In the case of China, it’s only for one day. 6th of every month, 3:00 am ~ 7th, 3:00 am
We used to envy China, but the thought that ‘in fact, China’s 66-day double event may be a stingy event, too’ comes to my mind.
At first, I thought the same way and raised an objection as you (there was a conversation between you and me in the past winds of fortune post),
But I changed my thought to that ‘the rewards are not that big and they’re free, then let’s just receive them’.
Reason for raising an objection in the past : Because they didn’t do like this in the 2nd anniversary goblin event, which was the beginning of this event.
But they have been constantly refining this event to suit their own interests.