Take apart the clock core of quartz clock and look at its power heart: permanent magnet wheel driven by electromagnet. The permanent magnet wheel is divided according to a certain diameter, half of which is N pole and half is S pole. The poles of the electromagnet are located on both sides of the permanent magnet wheel, and the electromagnet is controlled by the circuit, and the polarity is changed once every second, so the permanent magnet wheel rotates 180 degrees every second, and the second hand is driven by the gear.
Every time the polarity of the electromagnet is reversed, the permanent magnet wheel can be stabilized by rotating clockwise 180 degrees and counterclockwise 180 degrees, so the second hand can actually rotate clockwise or counterclockwise. As for why it usually turns clockwise, I really don't know. It may be that some measures have been taken mechanically to make the clockwise trend bigger. But for a normal quartz clock, you can gently press the second hand counterclockwise with the test strip (but don't directly cause the second hand to rotate), and you will find that the second hand will move counterclockwise by one square every second under external pressure. If the second hand is pressed long enough, the hour hand and the minute hand will also go counterclockwise.
So what you may see is that there were some external disturbances (airflow, magnetic field, gravity asymmetry of the second hand) at that time, which made the trend of counterclockwise rotation stronger.