What are the specific circumstances under which the US allowed the Pentagon to postpone the implementation of the Huawei ban?

What are the specific circumstances under which the US allowed the Pentagon to postpone the implementation of the Huawei ban? US media: Trump administration allows Pentagon to postpone implementation of Huawei ban until September 30

On August 14, the U.S. Defense News website reported that a memo obtained by the agency showed that the Trump administration granted the U.S. Department of Defense an exemption from the "Huawei ban", and the implementation of the department's ban could be postponed until September 30.
This means that Pentagon contractors can continue to use products and equipment from Chinese companies such as Huawei within the deadline.
According to reports, the ban was originally scheduled to take effect on August 13 this year. According to Section 889 of the 2019 National Defense Authorization Act, it will prohibit the US government from signing (contracting) contracts with companies whose supply chains include equipment products from five Chinese companies including Huawei.
According to Reuters, the five Chinese companies include Huawei, Hikvision, Dahua, Hytera and ZTE. U.S. government contractors covered by this ban need to prove that their companies will not use products from these Chinese companies unless they obtain a government exemption.