https://wccftech.com/crashing-iphone-apple-china-vietnam/

Apple reportedly altered some code to help China not get too angry over its “Taiwanese claim.” Since 2017, iOS tried to censor Taiwanese flag emoji when an iPhone was being used in China, making the people in the country believe that Taiwan didn’t exist at all. [China doesn’t recognize Taiwan’s independence]

Texts that used the emoji would display a box with a cross over it – a case of missing emoji. However, a side effect of this localized censorship was iPhone crashes and DOS attacks. On the side of the recipient, whenever an app would show the flag emoji, it would end up crashing. If someone with their location set to China would try typing “Taiwan,” their iPhone would crash, as well.