Please check whether the buffer mechanism is installed abnormally, as shown in the figure.
1. First, use the S2.0 Allen key to unscrew the two screws that fix the buffer mechanism cover.
2. Then use the S2.5 Allen key to unscrew the two screws that fix the buffer mechanism cover.
3. Finally, make the four buffer mechanisms consistent and install them in place again.
4. Check whether the buffer mechanism runs smoothly.