Is the roll running the correct way, the belt has to be crossed to run the roll into the chopper and make sure the metal flap is all the way back against the back of the tail or it will plug.
The hyd drive infeed roller should stop any plugging problems. If the bean stems are all dry then you should be having trouble. A few green ones can get you though. After all the years of NH having infeed rollers on TR choppers it makes you wonder what engineer was braindead when they made the CR standard chopper only have an infeed roll as an option.