Underneath the grill there is a piece of tape with a hole in the middle probably placed wrong or having a too small hole. It could also be the piece of tape to the left of the reflector that is covering the light.
I have removed both these on my device as I had this issue before
I also switched the backside from white to grey/black backside a month ago.
And I noticed that the light get dimmed no matter what so my theory is that 3'rd party non original parts do not fit as good as if I would have bought original parts. It could be the case because they look identical on the outside. The difference is that 3'rd party parts is not stamped with a serial number or partnumber and they might fit slightly different and need adjustment
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?