This is purely speculation as I have only the same information as you, the letter from Keystone as it was published. For anyone who wants to see the actual recall, it's online at:
http://www.keystonerv.com/media/9113...acks_-_web.pdf
My "guess" is that when they were installing the jacks "during assembly of the frame", someone used regular nuts, not nylocks on the jacks. On my XLite, there are 4 bolts that attach each jack to the jack plate that's welded to the frame rail. Two (not four) of those bolts have nylock nuts and two have regular nuts. The two (you guess which) consistently loosened, so I installed nylocks on all the bolts and no problems since. I'd suspect that what you'll find is that your jacks were installed with conventional nuts that could "work loose and cause the jack to fail during travel"....
If I were you, I wouldn't consider it a "oh goodness, go to the dealer in the morning" kind of recall. Chances are it's easily remedied by finding the owner's manual for the jacks (in your owner's packet) and verifying that the jacks are installed per the instructions. Then, after you've verified the installation, the next time you have the trailer at the dealer's service center, let them do the "recall inspection and paperwork" to clear the system.
Anyone who wants to verify the recall status of their trailer can do so at:
http://www.keystonerv.com/customer-s...-notifications Just select your specific brand and review the recall history on all trailers in that lineup.