No way to solve it, except sending to nokia care... the little led is weak, or it lost the glue, so its a little far from the screen. If you want to try ( i would not) you can open the phone, and see if its the glue
i had an 928 with an similar problem. I used to fix all my cellphones, exchanged 2 screens on galaxy s, audio jack on s2, and the buttons light (like yours) on motorola atrix.
After all these, i decided not to fix then anymore, since it seens it never gets really good.. sometimes it looks loose, sometimes dust behind screen.. its a pain