i’m a little confused, and i think there’s a little more to this…
in the screenshots in the original post, the second item in the first photo (list view) shows the Simplified form (“鸟类”) of “birds”. but in the second photo (grid view), the same item is displayed in Traditional (“鳥類”). your settings menu screenshot seems to be in Simplified. for example, the “language” menu item is displayed as “语言” (Simplified) as opposed to “語言” (Traditional).
when i change the language in the iNat app on Android 11 to Simplified, i do see some strangeness in both grid view item names and list view item names.
sometimes i see Simplified common names (Pomacea maculata, the first item on the list):
sometimes i see Traditional common names (Pomacea maculata, the first item on the list):
sometimes i see English common names (ex. “birds” towards the bottom of the screenshot):
so it seems that it’s not that Simplified names are not being displayed. It’s that they seem to be displayed inconsistently, possibly in conjunction with Traditional and even English?
it’s worth noting that when set my app language to Traditional (Taiwan), i see a similar mix of Simplified, Traditional, and English names. (the menus and headers, etc. seem to be in the right language.)
since something similar is being noted in https://forum.inaturalist.org/t/chinese-simplified-common-names-dont-show-in-the-suggestion/17732/3, i suspect these things are related.