It happens on the final Boss Umarghk (I didn't notice if it happens on lesser bosses). If you farm Boons before attempting it, there is a 50% chance they wont be loaded when you enter. Apparently the glitch only happens when PT members trade different books. In any case I'm dont with this boss now, after spending millions of gils to get the item I wanted... finally got what we wanted. The Abateur subligars is ~5% drop rate and at 3~6 Million OR 25 pheromons (3 weeks) per pop, it sucks. Its safe to say that Bonus to spoil is useless too: either it doesnt load, or if it loads it does nothing.