Vincent Pang, the President of Huawei's Western European Region, told TechRadar that 5G's slow rollout is the reason for the delay, not the ongoing trade war between the U.S and China. Apparently, Huawei is waiting for 5G to be more widely implemented in China and other important markets. This also means that the Mate X will be launched in any market with 5G connectivity.
When asked if Huawei is doing anything to ensure that the Mate X does not suffer the same fate as the Galaxy Fold, Pang said that it's a secret. He added that the company has "done a lot of tests" to ensure the durability of the plastic OLED panel.