I am sure you are not the only one who is thinking on this line. No one actually knows, except CFA Institute, if all candidates write the same exam even when the exam is on the same date around the world.
My feeling is, there might be few different versions of the exam question paper, due to different time zones, to protect the privacy and confidentiality of the exam questions. However, not very sure.
CFA Institute would have definitely thought about how can this issue be avoided before deciding to conduct the exam on two different dates.
Chill out man. The reason they’re doing this is not to cater to the fasting islams. It’s because there’s a testing center in Beijing somewhere that had over 10,000 level 1 candidates this year and they cannot effectively give the exam to soooo many people under the same conditions in one day (plus, one bathroom can only handle so much). I am quite confident that the “alt date” is offered for level 1 only. And that the level 2 & 3 people in the Asia pacific region will take it on the same day we do.
The alternate date is for all levels, and is for religious reasons. It’s not due to the volume of candidates; you must have a religious reason that you’re unable to take the exam on the Saturday (Shabbat for example). A Jewish friend of mine wrote the exam on the Sunday each year instead of Saturday since she observed Shabbat.
If so, I find it really weird that CFAI’s Twitter account explained the reason was the following "The change was made to avoid conflicting with the observance of Ramadan and the associated holiday and events."
But yeah, obviously you’re operating with a higher level of knowledge than I am. I think you should inform CFAI that their twitter has been hacked or something.