This is an issue with the speed and power setting you have chosen, and how Ruida deals with ramping power for direction changes.
Ruida has a ‘Start Speed’ or corner speed which is the point the tube will start to fire and ramp power to the max setting as it accelerates. Below that speed, the laser will use min power and if that is set low, you will not get a beam in the corners. If you want to go slow for cuts, set both min and max the same.
I recently provided another response to the same question here:
As for the marks you see on the back side, these are from flash backs, or when the beam penetrates the material and then bounces or is reflected off your honeycomb bed underneath, causing a quick flash or burn in that spot. You can observe this as the job runs, you will see the flash happening as the cut progresses. If you raise the material up off the bed, on pins or some such, you can reduce this effect significantly.