Rastering not uniform, how can i fix this issue?

Kind of hard to tell in the picture, I will take another next job i do. Is this a table problem or a laser problem?

What is the lens focal length? Is your laser bed plane flat and/or is the material lied down flat in relation to the laser head? What’s the laser tube power and speed/power settings that cause this issue? Do you see this problem less or more with other settings combination(s)?