On occasion, the AHS DB will not have a color description. Often time it's a very old cultivar. And then there are rules about not releasing data details on new intros until publication the following year. (for example... http://www.daylilies.org/Dayli...
My guess would be that since Mexican Fiesta is a 2014 intro, it was listed in our DB as such, but the data details had not been released yet on the AHS site . Therefore Mexican Fiesta got listed in the DB but without it's date details. Now they are and those cultivars need updating.
As far as it auto-updating, sure that's possible, but Dave would have to send a bot into motion for it to collect that new data. I'm pretty sure he does not a bot to constantly 'crawl' through the AHS site to auto detect when new info is added. (Total guess work on my part here, though)