Trampa ATB Motor Mount and Rocks

Anyone else have issues with rocks and their Trampa Motor Mount setup? I had a rock get caught between the idler and belt for the second time in less than two weeks of riding it. Happened at about 20mph this last time. Made me pucker a bit as I rode it out. Thank goodness for bindings. I decided to bend an acrylic cover for the belt drive to prevent it from happening again.