The closing bracket "}" can't be used in cloze question type

"}" can not be used in cloze type questions. Also "}" does not work. If one uses "{}" the display is correct, but the correct answer is not recognised as correct.

Example:
a) A = E1 Ç E5 = {2:SHORTANSWER:%100%

{}#Leere Menge~*#Es gibt keine Elemente in dieser Menge}

the correct answer should be: {}
But it is not accepted as correct. If you let give the system the correct answer it gives you {}. But if you submit this, it is said to be wrong.