If material is not traveling to discharge well you will grind straw and send to the distribution augers. Too much straw will plug distribution augers. It may be time for you to upgrade cylinder bars and helicals. Be sure all belts involved in driving the augers are in good condition and not sliping. Check auger to see the flighing isn't worn rounded. Accelerator rolls may be bad so they are not pulling material away from the augers.