Bmw 750li

bmw-7-seriesHey I have a BMW 750li . My passenger rear wheel grinds when I make a right or a left turn . I turn right ,It will grind for about two seconds and then pops into place….. Then no more noise . Then i will ride for a while and I turn left again ,it will grind for about two seconds then pops into place.then no more noise …..I find it funny because I thought the rear wheels were not supposed to turn just go straight.any help is appreciated