There is no blog article yet, but a email has been sent to some people who pre-ordered the AMD version.

Unfortunately, due to electrical issues we recently found during validation along with late firmware delivery from our silicon vendors, we’ve had to delay the start of mass production for Framework Laptop 13 (Ryzen 7040 Series) until September. We’ll be shipping as many pre-orders as we can before the end of September, but we anticipate that many orders originally in Q3 batches will need to move into Q4. We have prepared substantial production capacity, so we don’t expect the late start to cascade into delays in later batches.

The reason is basically (as far as I understand) because this is the latest iteration of a product, and many drivers are not ready for the product, hence making it hard to conduct effective testing.

And also there are serveral small complications with new hardwares (again, paraphrasing the email):

• The back USB-A expansion card will draw high amount of power when it is empty or pluged in with a USB 2.0 device
• The back HDMI/DP will draw high amount of power, but they are working on fixing the issue through firmware
• The windows installer do not come with the up-to-date wifi driver, yet requires user to log into a microsoft account
• Some linux distro with older kernel might not have ~~wifi~~ good general support out of the box, until updating the kernel, which probably will be covered by either official guide or community guide.

Fortunately, other expansion card like storage, USB-C, and USB-3.0 works fine, and they state that Fedora 38 "will work smoothly out of the box". And they are working on fixing all of these issue or provide detailed guide to tweak these issue yourself.