Hi, I’m not sure if it is a bug or just an inconsistency with the data the translation is based on.
My learning language is Chinese Simplified, and my translation language is German.
I’m referring to the Translation tool in the right drawer (possibly called MUI, I’m not sure). For example, some words don’t appear, while others do, as shown in the attached screenshots.
Perhaps I’m doing something wrong, but if I type ‘Handy’ into the translation field, ‘手机’ should appear, but it doesn’t. If I search in Hanzi, it does.
This is just an example; although it doesn’t happen all the time, it occurs frequently. For instance, Sonnenuntergang in both directions works.
However, 
Thank you for this tremendous and impressive PWA.