The sale stated it ended at UTC+8 on the 4th.
For those in the U.K., that was 8 am.
In the US using EST, that was 3 am.
It was clearly stated on the banner for the sale and in the terms.
I am the first (and often) to highlight things BL fail to share, this was not one of them. It was public and available on the sale page.
I am not sure what else they could have done.
You can see in the link above that I reminded other people, they were in Europe.
This banner for the sale shows the times in Pacific Standard Time (PST), which shows the same thing, that is midnight PST, 3am EST and 8AM GMT.