Hi Patrick,
thanks for bringing this issue to my attention. It turns out that this problem has existed for quite while. I have fixed it now in the QuizPort module (Moodle 1.x), the TaskChain module (Moodle 2.x) and the HotPot module for Moodle 2.x.
Please update your Moodle plugins when you next have a chance.
best regards
Gordon