The mob spawn rate has been heavily curtailed. It was previously a little too high - one could end up being unable to disengage - but it's now been slashed so far that I just gave up and went off to do something else in the end. As did the other person also waiting.
Since this is a daily quest, and everyone gets it at the same time, there will be huge numbers of people queuing up for the now overly scarce resource.
(I'd go back to 60% of the previous rate.)