building at 613 East 6th Street

Halstead has had the 1B duplex unit listed in this building on and off for almost two years. It started in the high 700's and is now priced at 649K. I think it went into contract once over a year ago, but never closed. Does anyone know anything about this? The building is good, the block is one of the better ones in the East Village, but the unit is about 600 sq/ft, ground floor, nine feet at it's widest, small spiral staircase, front of building etc. Apart from probably being priced too high, was wondering if there was some other underlying problem that's keeping it from moving.