Two days ago I had my JK parked behind my house, the driveway has a slight incline to it. The next day I went out to go to the store and when I pushed the clutch in it immediately rolled backwards, the parking brake was set. When I pushed the brake pedal it almost went to the floor, it was like this for a few minutes after I started the engine, then it was normal again. I have never had an issue like this in any vehicle I have owned in the past. Has anyone else experienced this???