If they haven't changed from gel coat to a painted front cap, your best bet is to keep an eye on it and get it in before your warranty is up. I would suggest at least a few months before the warranty is up, as most dealers are slow to do anything and you don't want to take any chances of them trying to wiggle out of fixing it. If you try to prevent it you may prolong it...but I'm willing to bet money it will fade eventually not matter what you do. Then you are stuck with a faded front cap outside of your warranty. If you get it painted before your year is up it will last much much longer, and you won't have to pay for it. Our 2016 got painted 7 months after we purchased it and I'm glad we did. It looks great and now I don't have to worry about the fixing the design flaw on my dime.
2016 Sunset Trail Reserve ST30RK
2013 F-150 Lariat EcoBoost
Oliver, the Rottweiler