Hi there! I’m one of the engineers who worked on the Form 3. I’m sorry to hear your printer is acting up.
I agree with @mh1974, that sounds like one of the stepper motors skipping (most likely, the motor that moves the LPU back and forth across the tank). There are a number of reasons this could happen. For example, something could be obstructing the motion of the LPU, there might be a problem with the limit switch that the printer uses to “home” the LPU.
This is an issue that our support team will be able to help you with, so please reach out to them if you haven’t already: