Upgrading shouldn't be too big of a deal, but it is an extra job that someone has to do, and it would be very understandable if the system admins prefer to do the upgrade during a weekend or half-term, when the server may not be so busy. Actually, the fix was only 3 lines of code in one file, "mod/quizport/class.php", but even so they may feel they want to test it somewhere before releasing on the live system.
This issue only affects QuizPorts that have different possible paths through the quizzes, which may lead to a student finishing the unit without necessarily doing all the quizzes. Where the QuizPort quizzes have no conditions, or conditions such that the students will always end up doing all the quizzes, there is no need to rush to be updated.
regards
Gordon