Scheduled product page showing up at different times for customers around the world

We did a highly anticipated new product drop this past week, which we new was going to be a flash sale. We alerted everyone to the day and time of the drop through our newsletter and our social media posts, so everyone was anticipating the products to go live on our site at 12:00pm EDT. The product pages were created, and scheduled to turn active at 12:00pm EDT.

But after the drop, we had many customers complain that the products did not appear on the site until 6 or 7 minutes after 12:00pm, by which time the products were sold out. Sales started flowing in at around 20 seconds after 12:00pm, so I know that many people were able to see the products on our site in order to buy them.

Does scheduling a product page to become active at a specific day and time not make it available to everyone around the globe at the same exact time?