Treadmill speeds up at incline

I got a 2950 delivered today. First workout I tried was a mountain hike, which took the incline up to 15% almost immediately. As soon as it got up to incline, the treadmill started moving way faster than the 2 MPH it was supposed to be going. It doesn't feel or sound like the belt is slipping, but I'm too new to this thing to say for sure. Has anyone else experienced this, or know how to fix it?