Anti -crease function has operated
If you have selected one of the auto sense programmes the machine will automatically end the drying cycle when the clothes are dry. To prevent them from creasing, the drum will occasionally turn until you open the door or switch the machine off.
This is may look like the machine is running continuously but is a very energy efficient way of reducing creases in the garments and is not a fault with the machine.
Always disconnect your appliance from the mains before you start examining it!