I've seen this happen a times, usually the operator for got to set the chopper to slow speed, or took the stationary knives completely out, allowing busted cob and debris to go thru pan slots.
my brothers had this same problem. it was a hole in the bottom of under the straw chopper. the way they fixed it was to take off knives from pan put the pan back up to the chopper as you use it in beans. good luck bill