https://www.cnet.com/news/iphone-crash-might-have-been-chinas-dislike-for-taiwans-flag/

An apparent Apple censorship feature reportedly led to an iPhone bug involving the Taiwan flag emoji. 

Since as early as the beginning of 2017, iOS has reportedly had a censorship function in which switching an iPhone's location setting to China -- which doesn't recognize Taiwan to be an independent entity -- makes the Taiwanese flag emoji disappear. Any text that features the emoji just shows a "missing" emoji.