Its not an exploit it's a smart strategy. and one that Gree was probably aware of before the first player ever had the bright idea. Despite popular opinion Gree's not stupid. after all they have a lot of us lining their pockets with our hard earned money. Why do you think the first half of prestige is a repeat of normal mode. They are having us reset the maps for prestige. If entertaining game play was their goal i would think they would be a little more creative then repeating missions.
I highly doubt this last ltq was an endevor to offset the prestaging. probably just a bad business decision. they aren't stupid but their not rocket scientists either