Laser master 3 alinement in offset fill

Offset fill especially at the high speeds that you are running are exceptionally mechanically challenging to the machine.
It’s likely exposing weak areas of the machine. Check belt tension and make sure that pinion gears are properly secured to the flats of the stepper motor.
If that doesn’t correct the issue then you may be just moving more quickly than your machine is capable of and your machine is losing steps. In that case slow down to see if that addresses the issue.