2005 z4 squeak in the rear suspension

this problems comes and goes but when I get into the car I hear this noise from the back drivers side maybe a bushing or something -any ideas--dealer states they can't find anything but that doesn't surprise me as it's intermittent.

Do you have the e-brake on when getting into and out of vehicle? If so, that is mostly likely it.

e brake is off and you can sit on the door sill and make the noise, I think I need to get under the car to see what's up....sounds more like suspension issue.