Target single pass cut values for your speeds/feeds. You are moving way too fast to effectively cut 6mm stock… You have to give the tool time to do it’s job or work.
Multiple passes increase the likelihood of many issues. A cutter does it’s best work with a single pass.
This is my 40W China Blue with 5mm sub flooring from Home Depot.
You should be able to do better than this with at least 50% more power and on basswood… sub flooring is pretty tough, unpredictable and has large variations in the same sheet… but it is very cheap.
As @ednisley advised, post a few photos of the target, especially at m1.
A burnt through hole or a black circle doesn’t tell us anything. The spot should be dark in the center and get lighter as it radiates outward.
Anytime you do or check an alignment checking the TEM mode of the tube can be checked when you verify the spot on m1 is centered.
If the tube is OK, then a recheck with target photos of the various setup points for a proper alignment would be the next logical step.
Good luck
