This issue is usually caused by the cutting carriage becoming loose from the guide rail. When the carriage is not firmly fixed, the blade cannot follow an accurate circular path, resulting in distorted shapes.
Please check whether your cutting carriage has the same problem shown in the video below:
To fix this issue, you need to re-secure the carriage firmly onto the guide rail.
Please follow the detailed repair steps in the video to ensure the carriage is correctly positioned and tightened.