I'm pretty sure there was a post a little while back that stated when they extended the time it did something funny with the timer and that the goal was going to expire with 3 hours left on the timer. It's somewhere in this thread.
Either way I couldn't get either dragon despite my constant harvesting. Oh we'll. it seems all of the Halloween Dragons have been impossible on my account except for the ugly zombie that I could have lived without. I'm about over this game.