The current default font used for Wikimedia Maps for East Asian Ideographs is a Japanese font. Some Chinese (traditional/simplified) characters share same code point as some Japanese characters in Unicode, however they use different glyphs. To render those characters correctly, it should use traditional/simplified Chinese fonts when simplified/traditional Chinese language maps are requested.
Also, somewhat related, when rendering the map at https://maps.wikimedia.org/?lang=zh#15/10.6986/106.7430 , the name of openstreetmap relation 7157197 was rendered without an appropriate character, and resulted in a "tofu" empty box character instead of the character it's supposed to be rendered. The text are 茹𦨭县 which should be rendered as https://i.imgur.com/g3gfUew.png but it is currently rendered as https://i.imgur.com/S3AlPC2.png