There is a possibility that iLaser was selected as the Device Profile when the AtomStack was set up.
We can verify if it’s this by selecting File, Save GCode and copying the first 10 or so lines of that file into a reply here.
If it happened there’s a fairly simple fix.
In the Laser window, click Devices, click Create Manually, and create a GRBL device profile.
If it’s something else, the first 10 or so lines of the file should still show it.