Most likely the front bar in the frame isn't going all the way back. The elastic straps wear out and don't pull the bar back enough when the top is lowering. Just give the bar a little nudge as the top passes aver your head and you should be fine.

Check this link for more info and a good fix.

 

Sit in your car with the top up and look straight up. There should be two elastic bands (one on either side of the car) that stretch from one crossbeam to another. Mine were all streched out and were just hanging. I took it back to the dealership and they replaced the straps under warranty. They are attached with four blind rivets. Good luck!