e-brake groan

Hi guys

I've got a 2004 corolla that when parked on a hill with the ebrake engaged, groans.(when there is movement ie getting out of the car) Is there a problem with the ebrake or is this normal?

Thanks

I have a 95 corolla that does the same thing. After you put it in park let it roll back(or forward) until it stops, then engage the parking brake.