I am using lightburn generated g code files on an SD card for my Falcon 2 40W. I run the frame on the board and everything is where I want it. When I start the burn it randomly moves left of the frame corner and starts burnig. It is very unpredictable where it will start. When I do the light burn files I have the start point in the lower left hand corner and use current location for the start position. I manually move the head to the lower left corner and power the laser up. It frames exactly where I want it to but when I hit start it shifts to far left and often hits the limit for side travel and stops.
Check Device Settings in Lightburn and “Enable laser offsetting” This is for the addition of a crosshair laser pointer on the side of the laser module. There are YouTube videos on how to make one as creality does not offer one to my knowledge. In your case you should disable this setting, or remove the X & Y offsets if they are present.
Do you start by homing the laser when you power it on? (press the house button in front of the laser). You should do this before starting to either frame or burn/cut so the laser knows where it is exactly.