Apple launched the iPhone 13 line alongside assurances that it would ship all of its variants on the same day in September 2021. Now, it has emerged that this is no longer the case. The delay affects the Pro and Pro Max only, and applies to their larger storage SKUs.
https://www.notebookcheck.net/Apple-pushes-iPhone-13-Pro-and-Pro-Max-shipping-dates-back-to-October-2021.562655.0.html