You need to check the beater/concave grater/fingers. They are on the back of the concave. If they are missing or bent you will get straw down into the sieves. Small pieces are common your straw looks bigger than that. So check out the concave fingers
There are two different types of fingers. Under serail number 11500 had straight individval fingers held in with a retainer. The Newer ones looked like a tuning fork and just had a bolt holding them between the two halves of the support.