The most recent update to the app has attempted to fix the problems with Chinese characters. Unfortunately it appears to have created a new problem. Here are two screenshots from a lesson on the website
Notice that all of the known known words, i.e. not the known LingQs, are not shown by the app. For example, look at the second character on the line next to the number 93. I have tested this with other lessons too. I also checked, and this doesn't happen in German (though when I read German on the iPad, I use the website and not the app).