The original process bonded the two halves together using the ledge/lip built into the part but there were bubbles visible from the front, like how glasses can make eyes look bigger. They switched to a process that put a crystal clear band on but people complained about not being able to use a fluid with Ethylene Glycol.

I told them people would hate that band if it were straw colored lol. To be fair, the one you have looks much thicker then normal and the protective paper on the acrylic mount adds some color. When filled it is not quite so noticeable, and of course is invisible when installed.