You have a really great question.
My first thoughts are that you may have had a recent price change that Trulia has not yet picked up. If this is not the case, you might want to supply them with your MLS information and the correct price so they can make the correction. You can reach them at: firstname.lastname@example.org
I too have had difficulties with Trulia. Most recently they have not even picked up 3 of my listings. When I contacted them because their system prevented me from manually loading the information, they advised me that my internet provider automatically downloads new listing information into the Trulia computers. Yet, none of the listings ever appeared. My provider checked everything out and said the problem is not on their end - talk with Trulia. Oh well, I guess the internet world is not perfect.
Good luck with finding the answer to your pricing problem.