The White House issued a stay on the ban until mid-August, allowing American companies to better prepare for breaking up ties with Huawei and betting on continued talks with China's trade negotiation team. According to Mr Wei:
That last claim seems to be another culprit behind the Mate X's delayed release. While the phone is equipped with the Balong 5000 modem of Huawei, the state of the 5G networks is such that requires further testing of the unique form factor. We'll see how the White House ban on working with Huawei pans out in mid-August but the company is growing leaps and bounds in its native China, so it will have at least something to compensate the market loss that the ban will inevitable bring about.
In any case, the Mate X should arrive by August 20, so not that much more to wait until we test its merits and pit it against the eventual re-released Samsung Galaxy Fold.