Hey guys,
Just a quick update - This same issue on my iPhone 6 finally got to the point where whatever piece of material that was covering the front lens was so noticeable and getting so bad that I finally scheduled a Genius Appointment to have it looked at. I was left with two options: 1) They would normally replace the entire front screen of my iPhone with a machine that they had in the back, which happened to be out of order at the time of my Genius appointment, so, I could wait until that was working again within the next few days/weeks or I could 2) Get the iPhone immediately replaced. I didn't really have much of a choice with the machine being broken so I authorized a replacement for my iPhone 6. The replacement iPhone 6 did come out of a "white box," which many people on this forum think means that the replacement "white box" iPhone is a refurbished iPhone, but I specifically asked the Genius if I would be getting a brand new phone or a refurbished phone as a replacement. He said this white box iPhone 6 is brand new, and he started to say something along the lines of how Apple always replaces broken iPhones with new iPhones that are covered under Apple Care or the one-year manufacturer warranty, and that "white box" iPhone replacements are separated during the manufacturing process to be used specifically for replacement purpose (hence the different box?). My guess is that the reason for this is so that a replacement phone is always available for users who have already bought the iPhone (which is the way it should be, after all).
I'll let you know if this new iPhone exhibits the same issue. God willing, it won't!