I unlocked 外れる on August 26th, 2015 (21 days after starting WaniKani), and nearly two years later… missed the burn again last week.
At 75 or so attempts, it isn’t even one I’ve missed the most (I know there are other items I have over 100 attempts at). It’s one that tends to get to master/enlightened, hang out there for a while and then show up right when I’ve re-confused it with others.
These leeches in general are so annoying, made a thread about it… Leech Squashing