Is 你跟家人一般见面？ a yes-no question? Duolingo translates

你跟家人一般见面？


as

When do you normally see your family?


However, I don't see why it is a question at all. I would translate

你跟家人一般见面


as

You normally see your family.


We can also make a question:

你跟家人一般见面吗？
Do you normally see your family?


or

你跟家人什么时候一般见面？
When do you normally see your family?


which is the translation Duolingo offers.

Who is right?
你跟家人一般见面？ is not a correct sentence. 

It should be 你跟家人一般什么时候见面？(When do you normally see your family?)