This is a fairly common problem. It is more likely to happen if you roll the jib up very tight, requiring more turns than usual. Rolling up the jib in high winds, especially if you use a winch on the furling line, will do this.
If you wait until you get back to the dock or in lesser winds, unwind the jib and roll it back up again. A slightly looser roll will leave you with some furling line left. And as Yngmar said, adding a couple of turns to the drum will fix it too.
Jake