Use the safe supply-isolation method immediately if it is accessible, and keep clear of the sink opening. Do not try to stop the mechanism with a utensil, stopper substitution or more food.
What the observation tells you
A failure of the normal control to stop the motor is different from a brief settling sound after rotation ends. Avoid repeated attempts to prove which control component has failed. Water near electrical parts or damaged switches makes hands-on investigation unsuitable.
A useful next step
Keep the supply isolated and arrange assessment of the appliance and control circuit. Describe exactly which control was used and whether the motor stopped only when its supply was disconnected.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.