Your going to need to adjust the accelerations. You will need to turn them up in the firmware. Pretty sure that is from the rapid stop and start everytime the laser turns on and off. I handle it by just slowing down my burn and turning down the laser instead of reflashing. If you decide to turn up the accel, you will want to raise up your material to keep the z axis at minimum length to keep it from resonating from high accel to keep your etching looking nice.
I don’t know anything about that laser but looks like you might need to be careful it has a 50% duty cycle, and it seems a little fishy the ad says 10w the driver says 3W, and in the middle it says average 6W.