Challenge 370 Cutter Clamp Safety Issue

[TimTrinity]

We have a 1999 Challenge 370 XG that recently started acting up. The clamp comes down under full pressure every time the cut buttons are pressed. The first time it failed my operator was not touching the buttons and the clamp came down. We had a local blade specialist look at the machine and he can't figure out the problem. So far Challenge has not replied to my emails about the problem but we are no longer using the machine since it's extremely dangerous. Has anyone else had an issue with the 370 clamp coming down under full pressure? Any input would be greatly appreciated.
Thanks.