Are you selling by owner or are you an agent? I'm an agent and if I enter a listing I can choose to enter it and syndicate from the MLS, from my own Brokerage listing service KWLS, or by hand typing it into Trulia. The latter requires address verification so it should map.
Sometimes it can take several days (I've heard up to a week) for changes to appear in Trulia, and I would presume that the software that feeds the typed in address is different from that which feeds the map. So patience is probably the best answer. If your listing has been live for more than a week, I would reach out to customer service at Trulia. Good luck selling your home!