Now that I figured out the problem with the ESR screen protector, I carefully positioned the glass cover in the jig, making sure the index tabs were tightly connected. This time, the screen protector went on perfectly, and when I assembled the Defender case around the iPhone, the darkened edges were perfectly positioned, and there were no bubbles under the glass.
I am wondering about The Defender case in all of the years I have used it, it has never left any part of the iPhone to be exposed. Now the camera control is. A lot of such cases are the same way. Is there a reason for this?