What about the orthography of 苹 (like in 苹果)? It seems consensus is missing
From a Unicode perspective it is the same character. Depending on the font and the environment you are using it may look different. Take for instance a look at the code charts of Unicode 12:



As can be seen above the Chinese and Japanese tend to write the same character slightly differently.

If you check what font and language that is used on Duolingo, you will probably find a Japanese version.