Whenever taking photos where there is very low light and the dual led flash is used produces this issue and not surprisingly taking the back cover off solves the issue and the same was with a fren of mine. Now I'll make him register if required just to vote on this one.
Also if nokia really decides to remanufacture back cover I would love to have ability to set stand in couple different positions like in n810 and make it more strong coz I'm scared to use it at all at the moment