Every time I try to perform the material test in LightBurn, the first row always cuts completely true, just like you can see in the photos. Who knows how I can fix it?
First step: measure and fill out the Scanning Offset Adjustment table to correct the extreme offset error:
Second step: For engraving, change the Material Test parameters to vary the speed from about 50 to 400 mm/s and the power from 10% to about 50%. That should give you better variation between the test squares.
Then you can make further tests in tighter ranges on specific materials.