Thank you for posting such detailed instructions! I have some clues now. This should be because I added the function of changing the color of selected options in the last update, and it is permanent for the entire game; this function works normally for Chinese, but Ren'Py's translation function is very detailed when it comes to options, and the color is also taken into account. So when the translated text needs to change color, it can't find the corresponding data.
Unfortunately, I can't update this error right now TT, D789 has been a struggle for me, and if I modify the translation at this point, a lot of things will go wrong (as I said, Ren'Py is very detailed about translation!) I will fix this error in the next D789 update.! (Also, there is no error in the settings! It's designed that way... to look good TT
This should be a bug that usually happens, and I'm shocked that no one has mentioned it before! Thank you for taking the time to edit these words, it helps a lot!!(*^▽^*)
Since I can't fix it at the moment, if you want to keep playing the game, you can try the following method: Use a screenshot translator! When Chinese text appears, you can translate it into English to read the text. (I usually use https://fanyi.youdao.com/; both have the web version or the app version.) Alternatively waiting for me to update the new version! This might take more than half a month or even a month, as the workload this time is quite substantial...TT