likely suffers from same disease as who's online page had.
namely, the line number shown is not reset back to 1 upon search.
so if you are not at the top of list, any search with less than x lines will give empty list as result. (x being the number of quest/person in list from the top)
so.. scroll down a bit, search for a quest with words that will give only ONE answer, get empty list.
or do so for who's online. get no name search, get full list of people on, search for anyone with full name, get empty list.
used to be resetable by clicking on scroll bar up arrow. (not trying to scroll it with mouse wheel or other means)
who's online side was reported (and not fixed) before update 9 and i have not tried if it applies for adventures but i heavily suspect so. why not copy/paste known "working" search function?