This is most likely to happen when the dough roller is being used. When using the dough roller, you should not lock the arm (and thus the roller) straight away, but should leave it resting against the bowl as it mixes the first few ingredients together. Let the Assistent operate at low speed as it does this. Once the dough starts to get so “firm” that it starts to climb, lock the roller 2-4 cm from the edge by pulling the arm towards the middle and turning the base knob. You can then increase the speed to medium.