Sorry, but no. Not based on what you have provided. Looking at your user profile I see you list your “Machines: CM-120” which is not clear what controller / firmware you are using to drive your laser. What OS, what version of LightBurn, type of laser (diode or co2), anything else that will allow us to better track down what you are seeing on your end.
Without a lot more details, I have nowhere to start offering technically accurate help. But if I had to guess, if the bed is not level, the beam will go out of focus when you move away from where you did the focusing as the bed will become closer or farther away when traveling to other parts of the bed. This could cause some places to cut and in other spots, not even mark the material as it is so out of focus that no energy is deposited in those spots. Poorly aligned or dirty/old mirrors and lenses can also cause beam output issues that will reduce the energy deposited as well.