The market fell so fast maybe they didn't have time to adjust their prices?
Does localbitcoins have an automated price change feature? (you can ask Bitstamp + 2%, for example & the displayed price changes with the market)
Yes they do have automated price adjustment. The ones who had a good price weren't selling and others raised their premiums. Same thing happened with precious metals when their price dropped. I remember people asking $24+ per silver oz when spot was around $18 last year.
Issue is also more evident in places where Bitcoin isn't as popular (smaller towns / cities), where there is less competition.