Some non-native English speakers may be learning a 3d language through English. While it isn't a correct form, a non-native speaker may use it and lose a heart... For some people it may be discouraging: after all, they only try to use the app to get to a third language and English for them is just a stepping stone, not a goal in itself. Possibly, the app creators had that in mind.
I am in the same situation but I dont think it's a problem. In this case I forgot the "does", I'll remember it next time, so I'm improving my english while I'm supposed to learn portugese, it's great ! :-)