Sounds like that "different noise" was the stepper(s) stalling and losing position.Today I cut 3 pockets, it did the first 2 fine, then when moving over to the 3rd one, it made a different noise and started cutting it it in totally the wrong direction.
Could be a lot of different things causing this.
Do you always here the stalling noise when this happens?Problem is, the machine seems to randomly go berzerk and start cutting in the wrong direction.
Make sure that all moving components are properly lubricated, and there is no binding anywhere in the machine.