"The teacher is waiting for a child."
Translation:A tanár egy gyereket vár.
I fully agree. The meaning of sentence "A tanár egy gyereket vár" is the exact same as that of "A tanár egy gyerekre vár". I will report it too.
There is one exception: "gyereket vár" can also mean expecting a child or in other words, pregnant, while "gyerekre vár" does not have this meaning.