You should be able to explain why you are reporting a problem because sometimes it is not covered by the options given to you.
For example I have been told that 'petit déjeuner' is a typo and it should be 'petit-déjeuner' - this is wrong and my answer was perfectly acceptable. However the only options available to report are a problem with the translation, the sentences being grammatically correct or the audio being unclear.
Similar things happen all the time.
There is a continual problem on the Russian program section 4 the correct answer is этому уеловеку нужно больше читать which th system shows as correct but when it is typed in the system refuses to accept it even thogh it is perfectly correct, it has been like that for over a month I have continually used the on screen reporting system with the red flag yet still it has not been corrected. Throughly frustrating as I have completed all the other sections and because ths fault is still there cannot move forward to the next section