Make sure that the thread path is unimpeded from the spool to the needle. When you program an automatic cut, enough thread is usually left in the needle to start the following sequence in the embroidery. Suppose something holds back the thread so that it cannot keep enough thread behind the needle, when the needle raises before the hoop moves to the new position. In that case, the shorter thread pulls out of the needle eye. This is especially noticeable with stacked spools on the vertical. They can not always quickly take enough thread from the spool.