Who else is affected by this bug. And by who else, I don't mean this one guy's customers / users. If the answer is no one else, or if no one else has reported it, then it's probably so far down the list as to be inconsequential. Which probably means the new guy on work experience gets to deal with it.

Not all bugs are fixed. There's only so many hours in the day, and some bugs are simply not worth fixing.